diff --git a/README.md b/README.md
index 7df39a2df..5fe9c0a43 100644
--- a/README.md
+++ b/README.md
@@ -229,7 +229,7 @@ static class HowTo_Assemble {
         // To broadcast memory, use the __dword_bcst/__qword_bcst memory types
         c.vunpcklps(xmm2.k5.z, xmm6, __dword_bcst[rax]);
 
-        // You can create anonymous labels, just like in eg. masm @F and @B
+        // You can create anonymous labels, just like in eg. masm, @@, @F and @B
         c.AnonymousLabel(); // same as @@: in masm
         c.inc(rax);
         c.je(c.@B); // reference the previous anonymous label
diff --git a/src/csharp/Intel/Iced.UnitTests/Intel/AssemblerTests/AssemblerLabelTests.cs b/src/csharp/Intel/Iced.UnitTests/Intel/AssemblerTests/AssemblerLabelTests.cs
index 53a4bba24..bd0f4821f 100644
--- a/src/csharp/Intel/Iced.UnitTests/Intel/AssemblerTests/AssemblerLabelTests.cs
+++ b/src/csharp/Intel/Iced.UnitTests/Intel/AssemblerTests/AssemblerLabelTests.cs
@@ -45,41 +45,41 @@ namespace Iced.UnitTests.Intel.AssemblerTests {
 
 		[Fact]
 		void Anonymous_labels() {
-            var c = new Assembler(64);
+			var c = new Assembler(64);
 
-            var lbl1 = c.CreateLabel();
-            var lbl2 = c.CreateLabel();
-            var lbl3 = c.CreateLabel();
-            var lbl4 = c.CreateLabel();
+			var lbl1 = c.CreateLabel();
+			var lbl2 = c.CreateLabel();
+			var lbl3 = c.CreateLabel();
+			var lbl4 = c.CreateLabel();
 
-            c.Label(ref lbl1);
-            c.inc(eax);
-            c.nop();
-            c.AnonymousLabel();
-            c.je(c.@B);
-            c.nop();
-            c.Label(ref lbl2);
-            c.je(c.@B);
-            c.nop();
-            c.jmp(lbl1);
-            c.nop();
-            c.jmp(lbl2);
-            c.nop();
-            c.jmp(lbl3);
-            c.nop();
-            c.jmp(lbl4);
-            c.nop();
-            c.jne(c.@F);
-            c.nop();
-            c.Label(ref lbl3);
-            c.jne(c.@F);
-            c.nop();
-            c.AnonymousLabel();
-            c.inc(eax);
-            c.nop();
-            c.Label(ref lbl4);
-            c.nop();
-            c.nop();
+			c.Label(ref lbl1);
+			c.inc(eax);
+			c.nop();
+			c.AnonymousLabel();
+			c.je(c.@B);
+			c.nop();
+			c.Label(ref lbl2);
+			c.je(c.@B);
+			c.nop();
+			c.jmp(lbl1);
+			c.nop();
+			c.jmp(lbl2);
+			c.nop();
+			c.jmp(lbl3);
+			c.nop();
+			c.jmp(lbl4);
+			c.nop();
+			c.jne(c.@F);
+			c.nop();
+			c.Label(ref lbl3);
+			c.jne(c.@F);
+			c.nop();
+			c.AnonymousLabel();
+			c.inc(eax);
+			c.nop();
+			c.Label(ref lbl4);
+			c.nop();
+			c.nop();
 
 			var expectedData = new byte[] {
 				0xFF, 0xC0, 0x90, 0x74, 0xFE, 0x90, 0x74, 0xFB, 0x90, 0xEB, 0xF5, 0x90, 0xEB, 0xF8, 0x90, 0xEB,
@@ -98,6 +98,22 @@ namespace Iced.UnitTests.Intel.AssemblerTests {
 			Assert.Throws<InvalidOperationException>(() => c.Assemble(new CodeWriterImpl(), 0));
 		}
 
+		[Fact]
+		void Undeclared_forward_anon_label_throws() {
+			var c = new Assembler(64);
+			c.nop();
+			c.je(c.@F);
+			Assert.Throws<InvalidOperationException>(() => c.Assemble(new CodeWriterImpl(), 0));
+		}
+
+		[Fact]
+		void At_most_one_anon_label_per_instruction() {
+			var c = new Assembler(64);
+			c.nop();
+			c.AnonymousLabel();
+			Assert.Throws<InvalidOperationException>(() => c.AnonymousLabel());
+		}
+
 		[Fact]
 		void Referencing_backward_anon_label_when_not_defined_throws() {
 			var c = new Assembler(64);
diff --git a/src/csharp/Intel/Iced/Intel/Assembler/Assembler.cs b/src/csharp/Intel/Iced/Intel/Assembler/Assembler.cs
index 0b63231cd..faeafbe17 100644
--- a/src/csharp/Intel/Iced/Intel/Assembler/Assembler.cs
+++ b/src/csharp/Intel/Iced/Intel/Assembler/Assembler.cs
@@ -127,10 +127,12 @@ namespace Iced.Intel {
 		}
 
 		/// <summary>
-		/// Creates an anonymous label that can be referenced by using the <see cref="B"/> (backward anonymous label)
+		/// Creates an anonymous label that can be referenced by using <see cref="B"/> (backward anonymous label)
 		/// and <see cref="F"/> (forward anonymous label).
 		/// </summary>
 		public void AnonymousLabel() {
+			if (_definedAnonLabel)
+				throw new InvalidOperationException("At most one anonymous label per instruction is allowed");
 			if (_nextAnonLabel.IsEmpty)
 				_currentAnonLabel = CreateLabel();
 			else
@@ -478,6 +480,11 @@ namespace Iced.Intel {
 				return false;
 			}
 
+			if (!_nextAnonLabel.IsEmpty) {
+				errorMessage = "Found an @F anonymous label reference but there was no call to " + nameof(AnonymousLabel);
+				return false;
+			}
+
 			var blocks = new[] { new InstructionBlock(writer, _instructions, rip) };
 			if (BlockEncoder.TryEncode(Bitness, blocks, out errorMessage, out var blockResults, options)) {
 				assemblerResult = new AssemblerResult(blockResults);