diff --git a/src/de/inetsoftware/jwebassembly/binary/BinaryModuleWriter.java b/src/de/inetsoftware/jwebassembly/binary/BinaryModuleWriter.java
index df3b412..50f1576 100644
--- a/src/de/inetsoftware/jwebassembly/binary/BinaryModuleWriter.java
+++ b/src/de/inetsoftware/jwebassembly/binary/BinaryModuleWriter.java
@@ -635,6 +635,10 @@ public class BinaryModuleWriter extends ModuleWriter implements InstructionOpcod
             case DROP:
                 codeStream.write( DROP );
                 break;
+            case BLOCK:
+                codeStream.write( BLOCK );
+                codeStream.write( 0x40 ); // void; the return type of the block. currently we does not use it
+                break;
             default:
                 throw new Error( "Unknown block: " + op );
         }
diff --git a/src/de/inetsoftware/jwebassembly/module/BlockOperator.java b/src/de/inetsoftware/jwebassembly/module/BlockOperator.java
index 15efdbe..16c5f68 100644
--- a/src/de/inetsoftware/jwebassembly/module/BlockOperator.java
+++ b/src/de/inetsoftware/jwebassembly/module/BlockOperator.java
@@ -29,4 +29,6 @@ public enum BlockOperator {
     END,
     GOTO,
     DROP,
+    BLOCK,
+    SWITCH,
 }
diff --git a/src/de/inetsoftware/jwebassembly/text/TextModuleWriter.java b/src/de/inetsoftware/jwebassembly/text/TextModuleWriter.java
index 2f3bfe3..ea6e3be 100644
--- a/src/de/inetsoftware/jwebassembly/text/TextModuleWriter.java
+++ b/src/de/inetsoftware/jwebassembly/text/TextModuleWriter.java
@@ -271,6 +271,10 @@ public class TextModuleWriter extends ModuleWriter {
             case DROP:
                 name = "drop";
                 break;
+            case BLOCK:
+                name = "block";
+                insetAfter++;
+                break;
             default:
                 throw new Error( "Unknown block: " + op );
         }