diff --git a/design.md b/design.md
index 4bfc922..65bc574 100644
--- a/design.md
+++ b/design.md
@@ -535,7 +535,6 @@ module Protocol
 			def initialize(request, deadline: nil)
 				@request = request
 				@deadline = deadline
-				@cancelled = false
 			end
 			
 			# @attribute [Protocol::HTTP::Request] The underlying HTTP request
@@ -562,17 +561,6 @@ module Protocol
 				@deadline ? [@deadline - Time.now, 0].max : nil
 			end
 			
-			# Mark this call as cancelled
-			def cancel!
-				@cancelled = true
-			end
-			
-			# Check if call was cancelled
-			# @returns [Boolean]
-			def cancelled?
-				@cancelled
-			end
-			
 			# Get peer information (client address)
 			# @returns [String | Nil]
 			def peer
diff --git a/lib/protocol/grpc/call.rb b/lib/protocol/grpc/call.rb
index e461c62..cbcd0d7 100644
--- a/lib/protocol/grpc/call.rb
+++ b/lib/protocol/grpc/call.rb
@@ -31,7 +31,6 @@ def initialize(request, response = nil, deadline: nil)
 				@request = request
 				@response = response
 				@deadline = deadline
-				@cancelled = false
 			end
 			
 			# @attribute [Protocol::HTTP::Request] The underlying HTTP request.
@@ -67,17 +66,6 @@ def time_remaining
 				@deadline&.remaining
 			end
 			
-			# Mark this call as cancelled.
-			def cancel!
-				@cancelled = true
-			end
-			
-			# Check if the call was cancelled.
-			# @returns [Boolean] `true` if the call was cancelled, `false` otherwise
-			def cancelled?
-				@cancelled
-			end
-			
 			# Get peer information (client address).
 			# @returns [String | Nil] The peer address as a string, or `Nil` if not available
 			def peer
diff --git a/releases.md b/releases.md
index 4d1c187..3386aa5 100644
--- a/releases.md
+++ b/releases.md
@@ -1,5 +1,9 @@
 # Releases
 
+## Unreleased
+
+  - **Breaking**: Removed the unused `Protocol::GRPC::Call#cancel!` and `Protocol::GRPC::Call#cancelled?` methods.
+
 ## v0.13.1
 
   - **Breaking**: Removed the deprecated `Protocol::GRPC::Methods` module. Use `Protocol::GRPC::Route`, `Protocol::GRPC::Metadata`, and `Protocol::GRPC::Header::Timeout` instead.
diff --git a/test/protocol/grpc/call.rb b/test/protocol/grpc/call.rb
index 7c6cd64..08ef9b1 100644
--- a/test/protocol/grpc/call.rb
+++ b/test/protocol/grpc/call.rb
@@ -63,17 +63,6 @@
 		end
 	end
 	
-	it "is not cancelled by default" do
-		call = subject.new(request)
-		expect(call).not.to be(:cancelled?)
-	end
-	
-	it "can be cancelled" do
-		call = subject.new(request)
-		call.cancel!
-		expect(call).to be(:cancelled?)
-	end
-	
 	with "deadline" do
 		let(:deadline) {Async::Deadline.start(5.0)}