diff --git a/src/main/java/com/google/api/generator/gapic/composer/DefaultValueComposer.java b/src/main/java/com/google/api/generator/gapic/composer/DefaultValueComposer.java
index 2994fef37b..161d7d725e 100644
--- a/src/main/java/com/google/api/generator/gapic/composer/DefaultValueComposer.java
+++ b/src/main/java/com/google/api/generator/gapic/composer/DefaultValueComposer.java
@@ -22,6 +22,7 @@
 import com.google.api.generator.engine.ast.StringObjectValue;
 import com.google.api.generator.engine.ast.TypeNode;
 import com.google.api.generator.engine.ast.ValueExpr;
+import com.google.api.generator.engine.ast.Variable;
 import com.google.api.generator.engine.ast.VariableExpr;
 import com.google.api.generator.gapic.model.Field;
 import com.google.api.generator.gapic.model.Message;
@@ -32,6 +33,7 @@
 import com.google.common.base.Preconditions;
 import com.google.longrunning.Operation;
 import com.google.protobuf.Any;
+import com.google.protobuf.ByteString;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
@@ -44,6 +46,8 @@ public class DefaultValueComposer {
   private static TypeNode OPERATION_TYPE =
       TypeNode.withReference(ConcreteReference.withClazz(Operation.class));
   private static TypeNode ANY_TYPE = TypeNode.withReference(ConcreteReference.withClazz(Any.class));
+  private static TypeNode BYTESTRING_TYPE =
+      TypeNode.withReference(ConcreteReference.withClazz(ByteString.class));
 
   static Expr createDefaultValue(
       MethodArgument methodArg, Map<String, ResourceName> resourceNames) {
@@ -122,6 +126,13 @@ static Expr createDefaultValue(Field f) {
           PrimitiveValue.builder().setType(f.type()).setValue("true").build());
     }
 
+    if (f.type().equals(BYTESTRING_TYPE)) {
+      return VariableExpr.builder()
+          .setStaticReferenceType(BYTESTRING_TYPE)
+          .setVariable(Variable.builder().setName("EMPTY").setType(BYTESTRING_TYPE).build())
+          .build();
+    }
+
     throw new UnsupportedOperationException(
         String.format(
             "Default value for field %s with type %s not implemented yet.", f.name(), f.type()));
diff --git a/src/test/java/com/google/api/generator/gapic/composer/DefaultValueComposerTest.java b/src/test/java/com/google/api/generator/gapic/composer/DefaultValueComposerTest.java
index 65371700bc..43f2507dad 100644
--- a/src/test/java/com/google/api/generator/gapic/composer/DefaultValueComposerTest.java
+++ b/src/test/java/com/google/api/generator/gapic/composer/DefaultValueComposerTest.java
@@ -17,6 +17,7 @@
 import static junit.framework.Assert.assertEquals;
 import static org.junit.Assert.assertThrows;
 
+import com.google.api.generator.engine.ast.ConcreteReference;
 import com.google.api.generator.engine.ast.Expr;
 import com.google.api.generator.engine.ast.TypeNode;
 import com.google.api.generator.engine.writer.JavaWriterVisitor;
@@ -24,6 +25,7 @@
 import com.google.api.generator.gapic.model.Message;
 import com.google.api.generator.gapic.model.ResourceName;
 import com.google.api.generator.gapic.protoparser.Parser;
+import com.google.protobuf.ByteString;
 import com.google.protobuf.Descriptors.FileDescriptor;
 import com.google.showcase.v1beta1.EchoOuterClass;
 import com.google.testgapic.v1beta1.LockerProto;
@@ -129,6 +131,18 @@ public void defaultValue_booleanField() {
     assertEquals("true", writerVisitor.write());
   }
 
+  @Test
+  public void defaultValue_byteStringField() {
+    Field field =
+        Field.builder()
+            .setName("foobar")
+            .setType(TypeNode.withReference(ConcreteReference.withClazz(ByteString.class)))
+            .build();
+    Expr expr = DefaultValueComposer.createDefaultValue(field);
+    expr.accept(writerVisitor);
+    assertEquals("ByteString.EMPTY", writerVisitor.write());
+  }
+
   @Test
   public void defaultValue_resourceNameWithOnePattern() {
     FileDescriptor lockerServiceFileDescriptor = LockerProto.getDescriptor();