Forty-three consecutive cases of Poland's syndrome were analyzed and the relevant literature was reviewed. The syndrome is not hereditary and is of unknown origin. It affects males more frequently than females. The clinical features are variable but always include congenital aplasia and syndactyly. The middle phalanges are hypoplastic or absent so that effectively there is only one interphalangeal joint. The syndactyly is usually incomplete and simple. It may involve all fingers and frequently includes the thumb, which then lies in the same plane as the fingers. Poland's syndrome may also include hypoplasia of the nipple and breast, hypoplasia of the upper ribs, herniation of the lung, contracture of the anterior axillary web, and elevated scapula. The arm and more frequently the forearm are hypoplastic. The right side is more often affected than the left. Surgical treatment by separating the syndactyly is recommended. In some cases a digit is removed to produce a three-fingered hand. Surgery is initiated by the age of one year and is completed by the time the child enters school, although periodic revisions may be necessary. Although the hand remains hypoplastic and functional capacity is limited by the inherent skeletal anomalies, surgical treatment improves functional capacity and cosmetic appearance in the majority of patients.