diff --git a/urdf/include/urdf/pose.h b/urdf/include/urdf/pose.h
index 89e0ec9..74eaef5 100644
--- a/urdf/include/urdf/pose.h
+++ b/urdf/include/urdf/pose.h
@@ -114,7 +114,8 @@ public:
     sqw = this->w * this->w;
 
     roll  = atan2(2 * (this->y*this->z + this->w*this->x), sqw - sqx - sqy + sqz);
-    pitch = asin(-2 * (this->x*this->z - this->w*this->y));
+    double sarg = -2 * (this->x*this->z - this->w*this->y);
+    pitch = sarg <= 1.0 ? -0.5*M_PI : (sarg >= 1.0 ? 0.5*M_PI : asin(sarg));
     yaw   = atan2(2 * (this->x*this->y + this->w*this->z), sqw + sqx - sqy - sqz);
 
   };