diff --git a/components/layout/layout_task.rs b/components/layout/layout_task.rs
index 28eacfd1763..f0aba98b393 100644
--- a/components/layout/layout_task.rs
+++ b/components/layout/layout_task.rs
@@ -834,19 +834,6 @@ impl LayoutTask {
                                               traversal);
     }
 
-    /// Verifies that every node was either marked as a leaf or as a nonleaf in the flow tree.
-    /// This is only on in debug builds.
-    #[inline(never)]
-    #[cfg(debug)]
-    fn verify_flow_tree(&self, layout_root: &mut FlowRef) {
-        let mut traversal = traversal::FlowTreeVerification;
-        layout_root.traverse_preorder(&mut traversal);
-    }
-
-    #[cfg(not(debug))]
-    fn verify_flow_tree(&self, _: &mut FlowRef) {
-    }
-
     fn process_node_geometry_request<'a>(&'a self,
                                       requested_node: TrustedNodeAddress,
                                       layout_root: &mut FlowRef,
@@ -1338,11 +1325,6 @@ impl LayoutTask {
                 }
             });
 
-            // Verification of the flow tree, which ensures that all nodes were either marked as
-            // leaves or as non-leaves. This becomes a no-op in release builds. (It is
-            // inconsequential to memory safety but is a useful debugging tool.)
-            self.verify_flow_tree(&mut root_flow);
-
             if opts::get().trace_layout {
                 layout_debug::begin_trace(root_flow.clone());
             }
diff --git a/components/layout/traversal.rs b/components/layout/traversal.rs
index 43199d7a05d..7742ee36582 100644
--- a/components/layout/traversal.rs
+++ b/components/layout/traversal.rs
@@ -292,23 +292,6 @@ impl<'a> PostorderDomTraversal for ConstructFlows<'a> {
     }
 }
 
-/// The flow tree verification traversal. This is only on in debug builds.
-#[cfg(debug)]
-struct FlowTreeVerification;
-
-#[cfg(debug)]
-impl PreorderFlow for FlowTreeVerification {
-    #[inline]
-    fn process(&mut self, flow: &mut Flow) {
-        let base = flow::base(flow);
-        if !base.flags.is_leaf() && !base.flags.is_nonleaf() {
-            println!("flow tree verification failed: flow wasn't a leaf or a nonleaf!");
-            flow.dump();
-            panic!("flow tree verification failed")
-        }
-    }
-}
-
 /// The bubble-inline-sizes traversal, the first part of layout computation. This computes
 /// preferred and intrinsic inline-sizes and bubbles them up the tree.
 pub struct BubbleISizes<'a> {