Stable internal fixation is essential to obtain healing of an ununited fracture of the proximal humerus. Standard plate and screw fixation may be inadequate to secure a small, osteopenic proximal fragment. We used blade plates and autogenous cancellous bone graft to repair ununited fractures of the proximal humerus in 25 patients (19 women and 6 men) with a mean age of 61 years. Healing was documented in 23 of 25 patients (92%). Objective and subjective instruments documented substantial functional improvement in patients with healed fractures. The results were classified as good or excellent in 20 of 25 patients, and few complications were encountered. Blade plate fixation facilitates successful treatment of ununited fractures of the proximal humerus.