Abstract: A letter opener is disclosed for cutting off the edge of an envelope which has a deformable U-shaped body. A cutting blade is located in the upper wall of the body, and a hole positioned to receive the blade is located in the lower wall. An abutment attached to the lower wall serves both as a guiding surface for an envelope, and as a stopper to prevent the two walls from binding against the envelope when pressed together. The device is used by placing a corner of an envelope against the abutment, pressing the two walls together causing the blade to puncture the envelope, and drawing the device along the edge of the envelope to thereby slice off that edge of the envelope.