Experimental scoliosis with the potential for marked progression was treated by rib resection without spinal fusion to investigate the corrective effect of rib resection on progressive scoliosis. Forty chickens were divided into two groups (groups A and B) and pinealectomy was performed at 3 days of age. In group B, three ribs were resected on the concave side if scoliosis of > 20 degrees developed before the age of 4 weeks. Spinal radiographs were taken until the age of 20 weeks at 4-week intervals to evaluate the scoliosis. Chickens in group A developed severe scoliosis (24-85 degrees) that progressed until 20 weeks of age, and chickens in group B showed mild scoliosis (6-56 degrees). Some degree of reprogression was found after early bone union at the sites of rib resection. Rib resection may be able to control progressive scoliosis when performed on the concave side of the curve.