diff --git a/a8/collision.cc b/a8/collision.cc
index cab0a23..07ed6f0 100644
--- a/a8/collision.cc
+++ b/a8/collision.cc
@@ -362,4 +362,16 @@ namespace a8
         }
         return true;
     }
+
+    bool IntersectCylinderCylinder(const glm::vec3& a_pos, float a_rad, float a_height,
+                                   const glm::vec3& b_pos, float b_rad, float b_height)
+    {
+        glm::vec2 v = glm::vec2(b_pos.x, b_pos.z) - glm::vec2(a_pos.x, a_pos.z);
+        float n = glm::length(v);
+        if (n > a_rad + b_rad) {
+            return false;
+        }
+        return (a_pos.y - b_pos.y) < (a_height + b_height) / 2.0f;
+    }
+
 }
diff --git a/a8/collision.h b/a8/collision.h
index 6585900..133b19e 100644
--- a/a8/collision.h
+++ b/a8/collision.h
@@ -16,6 +16,9 @@ namespace a8
                           float b_width,
                           float b_height);
     bool IntersectCircleCircle(a8::Vec2 a_pos, float a_rad, a8::Vec2 b_pos, float b_rad);
+    bool IntersectCylinderCylinder(const glm::vec3& a_pos, float a_rad, float a_height,
+                                   const glm::vec3& b_pos, float b_rad, float b_height);
+
     bool IntersectCircleArc(a8::Vec2 a_pos,
                             float a_rad,
                             a8::Vec2 b_pos,