diff --git a/src/de/inetsoftware/jwebassembly/binary/BinaryModuleWriter.java b/src/de/inetsoftware/jwebassembly/binary/BinaryModuleWriter.java
index 633b1c2..80627ff 100644
--- a/src/de/inetsoftware/jwebassembly/binary/BinaryModuleWriter.java
+++ b/src/de/inetsoftware/jwebassembly/binary/BinaryModuleWriter.java
@@ -1039,6 +1039,17 @@ public class BinaryModuleWriter extends ModuleWriter implements InstructionOpcod
                     default:
                 }
                 break;
+            case copysign:
+                switch( valueType ) {
+                    case f32:
+                        op = F32_COPYSIGN;
+                        break;
+                    case f64:
+                        op = F64_COPYSIGN;
+                        break;
+                    default:
+                }
+                break;
 
             default:
         }
diff --git a/src/de/inetsoftware/jwebassembly/wasm/NumericOperator.java b/src/de/inetsoftware/jwebassembly/wasm/NumericOperator.java
index d1dec44..bbb6b40 100644
--- a/src/de/inetsoftware/jwebassembly/wasm/NumericOperator.java
+++ b/src/de/inetsoftware/jwebassembly/wasm/NumericOperator.java
@@ -50,4 +50,5 @@ public enum NumericOperator {
     floor,
     trunc,
     nearest,
+    copysign,
 }
diff --git a/src/de/inetsoftware/jwebassembly/watparser/WatParser.java b/src/de/inetsoftware/jwebassembly/watparser/WatParser.java
index 00993f8..bdbbc2e 100644
--- a/src/de/inetsoftware/jwebassembly/watparser/WatParser.java
+++ b/src/de/inetsoftware/jwebassembly/watparser/WatParser.java
@@ -114,6 +114,9 @@ public class WatParser extends WasmCodeBuilder {
                     case "f32.reinterpret_i32":
                         addConvertInstruction( ValueTypeConvertion.i2f_re, javaCodePos, lineNumber );
                         break;
+                    case "f32.copysign":
+                        addNumericInstruction( NumericOperator.copysign, ValueType.f32, javaCodePos, lineNumber );
+                        break;
                     case "f32.sqrt":
                         addNumericInstruction( NumericOperator.sqrt, ValueType.f32, javaCodePos, lineNumber );
                         break;
@@ -153,6 +156,9 @@ public class WatParser extends WasmCodeBuilder {
                     case "f64.reinterpret_i64":
                         addConvertInstruction( ValueTypeConvertion.l2d_re, javaCodePos, lineNumber );
                         break;
+                    case "f64.copysign":
+                        addNumericInstruction( NumericOperator.copysign, ValueType.f64, javaCodePos, lineNumber );
+                        break;
                     case "f64.sqrt":
                         addNumericInstruction( NumericOperator.sqrt, ValueType.f64, javaCodePos, lineNumber );
                         break;