Abstract: The invention provides a device for threading an end of a guidewire into a catheter, the catheter having a tip connected to an inner lumen of the catheter, the inner lumen dimensioned to receive the guidewire therethrough. The device comprises: a guidewire receiving port; a catheter tip receiving port; a channel connecting the guidewire receiving port to the catheter tip receiving port. The channel is dimensioned to pass the outer thickness of the guidewire therethrough and the channel is dimensioned to block passage of the outer thickness of the catheter therethrough. A contiguous section of the guidewire receiving port, the catheter tip receiving port and the channel form an open passageway from which the guidewire and catheter, once the guidewire is threaded into the catheter, are disengaged from the device. The open passageway may be covered by a flap mounted to the device which releasably cover,s the contiguous open section of the guidewire receiving port, the catheter tip receiving port and the channel.