CONTEXT: Acromegalic patients may complain of sensory disturbances in their hands. Cubital tunnel syndrome, the ulnar nerve neuropathy at the cubital tunnel (UCT), in acromegalic patients has never been reported. OBJECTIVE: To describe and assess the prevalence of UCT in acromegalic patients and the effects of 1 year of therapy on UCT. PATIENTS: We examined prospectively 37 acromegalic patients with no history of polyneuropathy, acute trauma at the elbow, no diabetes or hypothyroidism with clinical examination, nerve conduction studies (NCS), and high-resolution ultrasound (US). A control group was made by 50 volunteers. The local ethics committee approved the study and written informed consent was obtained from all subjects involved in the study. INTERVENTION: Clinical history, physical examination, NCS, and US were used to diagnose UCT at the beginning of the study and after 1 year. RESULTS: In 8 of 37 patients, a diagnosis of UCT was made at the beginning of the study reflecting a prevalence of 21%. After 1 year, 5 of 8 (62.5%) patients reported clinical and NCS improvements and evident US reduction of nerve cross-sectional area (CSA; 16.7+/-2.9 mm(2) vs 12.2+/-3.1 mm(2); P<0.001). In 3 of 8 (37.5%) patients, the UCT was unchanged. Ulnar nerve CSA was significantly increased in acromegalic patients with UCT (16.7+/-2.9 mm(2) vs 11.1+/-2.3 mm(2); P<0.047). CONCLUSION: Ulnar neuropathy could occur in acromegalic patients and can improve in 62% of cases with disease control. Due to the different management and therapeutic approach, it would be important to make differential diagnosis between cubital and carpal tunnel syndrome in acromegaly.