diff --git a/dx/src/com/android/dx/cf/attrib/AttSourceDebugExtension.java b/dx/src/com/android/dx/cf/attrib/AttSourceDebugExtension.java
deleted file mode 100644
index 3dd4fec..0000000
--- a/dx/src/com/android/dx/cf/attrib/AttSourceDebugExtension.java
+++ /dev/null
@@ -1,62 +0,0 @@
-/*
- * Copyright (C) 2007 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.dx.cf.attrib;
-
-import com.android.dx.rop.cst.CstString;
-
-/**
- * Attribute class for standard {@code SourceDebugExtension} attributes.
- */
-public final class AttSourceDebugExtension extends BaseAttribute {
-    /** {@code non-null;} attribute name for attributes of this type */
-    public static final String ATTRIBUTE_NAME = "SourceDebugExtension";
-
-    /** {@code non-null;} Contents of SMAP */
-    private final CstString smapString;
-
-    /**
-     * Constructs an instance.
-     *
-     * @param smapString {@code non-null;} the SMAP data from the class file.
-     */
-    public AttSourceDebugExtension(CstString smapString) {
-        super(ATTRIBUTE_NAME);
-
-        if (smapString == null) {
-            throw new NullPointerException("smapString == null");
-        }
-
-        this.smapString = smapString;
-    }
-
-    /** {@inheritDoc} */
-    @Override
-    public int byteLength() {
-        // Add 6 for the standard attribute header: the attribute name
-        // index (2 bytes) and the attribute length (4 bytes).
-        return 6 + smapString.getUtf8Size();
-    }
-
-    /**
-     * Gets the SMAP data of this instance.
-     *
-     * @return {@code non-null;} the SMAP data.
-     */
-    public CstString getSmapString() {
-        return smapString;
-    }
-}
diff --git a/dx/src/com/android/dx/cf/direct/StdAttributeFactory.java b/dx/src/com/android/dx/cf/direct/StdAttributeFactory.java
index 710ba57..992809a 100644
--- a/dx/src/com/android/dx/cf/direct/StdAttributeFactory.java
+++ b/dx/src/com/android/dx/cf/direct/StdAttributeFactory.java
@@ -31,7 +31,6 @@
 import com.android.dx.cf.attrib.AttRuntimeVisibleAnnotations;
 import com.android.dx.cf.attrib.AttRuntimeVisibleParameterAnnotations;
 import com.android.dx.cf.attrib.AttSignature;
-import com.android.dx.cf.attrib.AttSourceDebugExtension;
 import com.android.dx.cf.attrib.AttSourceFile;
 import com.android.dx.cf.attrib.AttSynthetic;
 import com.android.dx.cf.attrib.InnerClassList;
@@ -104,9 +103,6 @@
                 if (name == AttSignature.ATTRIBUTE_NAME) {
                     return signature(cf, offset, length, observer);
                 }
-                if (name == AttSourceDebugExtension.ATTRIBUTE_NAME) {
-                    return sourceDebugExtension(cf, offset, length, observer);
-                }
                 if (name == AttSourceFile.ATTRIBUTE_NAME) {
                     return sourceFile(cf, offset, length, observer);
                 }
@@ -696,23 +692,6 @@
     }
 
     /**
-     * Parses a {@code SourceDebugExtesion} attribute.
-     */
-    private Attribute sourceDebugExtension(DirectClassFile cf, int offset, int length,
-                                           ParseObserver observer) {
-        ByteArray bytes = cf.getBytes().slice(offset, offset + length);
-        CstString smapString = new CstString(bytes);
-        Attribute result = new AttSourceDebugExtension(smapString);
-
-        if (observer != null) {
-            String decoded = smapString.getString();
-            observer.parsed(bytes, offset, length, "sourceDebugExtension: " + decoded);
-        }
-
-        return result;
-    }
-
-    /**
      * Parses a {@code SourceFile} attribute.
      */
     private Attribute sourceFile(DirectClassFile cf, int offset, int length,
diff --git a/dx/src/com/android/dx/dex/cf/AttributeTranslator.java b/dx/src/com/android/dx/dex/cf/AttributeTranslator.java
index 31f19c0..90e32c3 100644
--- a/dx/src/com/android/dx/dex/cf/AttributeTranslator.java
+++ b/dx/src/com/android/dx/dex/cf/AttributeTranslator.java
@@ -25,7 +25,6 @@
 import com.android.dx.cf.attrib.AttRuntimeVisibleAnnotations;
 import com.android.dx.cf.attrib.AttRuntimeVisibleParameterAnnotations;
 import com.android.dx.cf.attrib.AttSignature;
-import com.android.dx.cf.attrib.AttSourceDebugExtension;
 import com.android.dx.cf.attrib.InnerClassList;
 import com.android.dx.cf.direct.DirectClassFile;
 import com.android.dx.cf.iface.AttributeList;
@@ -89,16 +88,11 @@
     public static Annotations getAnnotations(AttributeList attribs) {
         Annotations result = getAnnotations0(attribs);
         Annotation signature = getSignature(attribs);
-        Annotation sourceDebugExtension = getSourceDebugExtension(attribs);
 
         if (signature != null) {
             result = Annotations.combine(result, signature);
         }
 
-        if (sourceDebugExtension != null) {
-            result = Annotations.combine(result, sourceDebugExtension);
-        }
-
         return result;
     }
 
@@ -220,18 +214,6 @@
         return AnnotationUtils.makeSignature(signature.getSignature());
     }
 
-
-    private static Annotation getSourceDebugExtension(AttributeList attribs) {
-        AttSourceDebugExtension extension = (AttSourceDebugExtension)
-            attribs.findFirst(AttSourceDebugExtension.ATTRIBUTE_NAME);
-
-        if (extension == null) {
-            return null;
-        }
-
-        return AnnotationUtils.makeSourceDebugExtension(extension.getSmapString());
-    }
-
     /**
      * Gets the {@code EnclosingMethod} attribute out of a given
      * {@link AttributeList}, if any, translating it to an annotation.
diff --git a/dx/src/com/android/dx/dex/file/AnnotationUtils.java b/dx/src/com/android/dx/dex/file/AnnotationUtils.java
index 109583e..6441522 100644
--- a/dx/src/com/android/dx/dex/file/AnnotationUtils.java
+++ b/dx/src/com/android/dx/dex/file/AnnotationUtils.java
@@ -62,10 +62,6 @@
     private static final CstType SIGNATURE_TYPE =
         CstType.intern(Type.intern("Ldalvik/annotation/Signature;"));
 
-        /** {@code non-null;} type for {@code SourceDebugExtension} annotations */
-    private static final CstType SOURCE_DEBUG_EXTENSION_TYPE =
-        CstType.intern(Type.intern("Ldalvik/annotation/SourceDebugExtension;"));
-
     /** {@code non-null;} type for {@code Throws} annotations */
     private static final CstType THROWS_TYPE =
         CstType.intern(Type.intern("Ldalvik/annotation/Throws;"));
@@ -224,20 +220,6 @@
     }
 
     /**
-     * Constructs a standard {@code SourceDebugExtension} annotation.
-     *
-     * @param smapString {@code non-null;} the SMAP string associated with
-     * @return {@code non-null;} the annotation
-     */
-    public static Annotation makeSourceDebugExtension(CstString smapString) {
-        Annotation result = new Annotation(SOURCE_DEBUG_EXTENSION_TYPE, SYSTEM);
-
-        result.put(new NameValuePair(VALUE_STRING, smapString));
-        result.setImmutable();
-        return result;
-    }
-
-    /**
      * Constructs a standard {@code Throws} annotation.
      *
      * @param types {@code non-null;} the list of thrown types
diff --git a/dx/tests/133-source-debug-extension/expected.txt b/dx/tests/133-source-debug-extension/expected.txt
deleted file mode 100644
index 04d943c..0000000
--- a/dx/tests/133-source-debug-extension/expected.txt
+++ /dev/null
@@ -1,4 +0,0 @@
-1c1
-< SourceDebugExtension
----
-> (Ldalvik/annotation/SourceDebugExtension;
diff --git a/dx/tests/133-source-debug-extension/info.txt b/dx/tests/133-source-debug-extension/info.txt
deleted file mode 100644
index 3bec03c..0000000
--- a/dx/tests/133-source-debug-extension/info.txt
+++ /dev/null
@@ -1,7 +0,0 @@
-This test checks that SourceDebugExtension information propagates from
-the class file to the DEX file emitted by dx. It extracts SMAP information
-from the class file and DEX file and checks the strings match.
-
-NB dalvik/dexdump does not have support for DEX annotations so the test
-just checks that the SMAP string appears in the DEX file and assumes
-it is packaged within an annotation.
diff --git a/dx/tests/133-source-debug-extension/run b/dx/tests/133-source-debug-extension/run
deleted file mode 100755
index 4c12360..0000000
--- a/dx/tests/133-source-debug-extension/run
+++ /dev/null
@@ -1,30 +0,0 @@
-#!/bin/bash
-#
-# Copyright (C) 2017 The Android Open Source Project
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-# Test runs in temporary directory created by test-run.
-
-test_class=HelloKt.class
-test_dex=HelloKt.dex
-
-# Generate DEX file
-dx --dex --output=$test_dex $test_class
-
-# Extract for SMAP string in DEX and class file.
-for i in $test_class $test_dex; do
-  strings $i | sed -n -e "/SourceDebugExtension/ p" -e "/SMAP/,/23/ p" > $i.output
-done
-
-diff $test_class.output $test_dex.output