The viability of a free radial forearm flap which is used in pharyngoesophageal reconstruction is difficult to monitor because it is hidden by skin. As the most reliable method for monitoring, exteriorization of a small island flap has been reported. The authors used a skin paddle which is placed ulnar to the radial forearm reconstruction flap at the ulnar side of the distal part of the forearm as a monitor flap in one patient. Flap viability was assessed by observing tissue color, turgor, capillary refill, and bleeding of the monitor flap. This monitor flap is easy to elevate. The perfusion of the flap is good because it has a wide pedicle. It permits a long vascular pedicle for the radial forearm reconstruction flap and does not reduce available forearm skin for pharyngoesophageal reconstruction.