diff --git a/lib/nack/headers.rb b/lib/nack/headers.rb
index c311936..bb01f9e 100644
--- a/lib/nack/headers.rb
+++ b/lib/nack/headers.rb
@@ -42,6 +42,11 @@ def delete(name)
       self
     end
 
+    def delete_if(&block)
+      @fields.reject!(&block)
+      self
+    end
+
     def to_a
       @fields.dup
     end
diff --git a/test/spec_headers.rb b/test/spec_headers.rb
index 647974d..aa14f4d 100644
--- a/test/spec_headers.rb
+++ b/test/spec_headers.rb
@@ -46,6 +46,12 @@
     headers.to_a.must_equal [["b", "2"]]
   end
 
+  it "deletes the fields the block selects" do
+    headers = Nack::Headers.new([["a", "1"], ["b", "2"], ["a", "3"]])
+    headers.delete_if { |name, value| name == "a" && value == "3" }.must_be_same_as headers
+    headers.to_a.must_equal [["a", "1"], ["b", "2"]]
+  end
+
   it "does not alias the internal storage" do
     fields = [["a", "1"], ["b", "2"], ["a", "3"]]
     headers = Nack::Headers.new(fields).add("c", "4")