Twenty patients with a mean age of 50 years old were treated with corrective osteotomy for the proximal humeral malunions, and were reviewed with a mean follow-up of 20 months. There were two valgus impacted 4-P malunions with greater tuberosity (GT) and lesser tuberosity (LT) osteotomies, three 3-P(GT) malunions with hemiarthroplasty by GT osteotomy, six 3-P(GT) and six 2-P(GT) malunions with GT osteotomy, two 2-P surgical neck (SN) malunions with valgus SN osteotomy, and a 2-P(LT) malunion with LT osteotomy. The initial fracture treatment was conservative in 14 cases and operative in 6 cases. The period from trauma to surgery was 20 months on an average. Postoperatively, pain was improved in 8 cases, and disappeared in 12 cases which included all 2-P(GT) malunions. The range of shoulder elevation was improved in 19 cases, but a 4-P malunion had decreased range of elevation. Bone union was achieved in all cases, but a 4-P malunion with the decreased range of elevation and a 3-P malunion with GT osteotomy were followed by avascular necrosis of the humeral head. Usefulness of the surgery for pain and restricted range of elevation were analyzed by age, initial treatment, period from trauma to surgery, and surgical procedures. Statistical analysis revealed patients under 50 years of age had a higher proportion of disappearance of the pain, and patients with conservative treatment had a higher range of preoperative elevation (p<0.05). Postoperative range of elevation was higher in 2-P(GT) and 2-P(SN), and the improved range of elevation was larger in 2-P(SN) (p<0.05). Corrective osteotomy for proximal humeral malunions is especially effective under 50 years of age, and for 2-P(GT) and 2-P(SN), but osteotomy for 4-P or 3-P malunions has a risk of avascular necrosis of the humeral head.