Purpose To study the utility of positron emission tomography with computerized tomography (PET/CT) in patients with a stage I–III melanoma. Patients and methods PET/CT findings from all patients with a stage I–III melanoma attended at our hospital from September 2011 to November 2015 were reviewed. Results Data from 83 patients with a stage I–III melanoma, 39 patients with a positive sentinel lymph node biopsy (SLNB) and 35 patients with locoregional recurrences were analyzed. Sensitivity of PET/CT in clinical stage I–III patients was 5%, with a 14% of false positives. In patients with a positive SLNB, PET/CT previous to complete lymph node dissection had a 23% of false negatives. In patients with clinical locoregional recurrences, PET/CT findings revealed asymptomatic visceral distant metastasis in 25.7%. Conclusions PET/CT has a significant rate of false positive and negative results in patients with a stage I–III melanoma. Utility in patients with nodal locoregional recurrences seems higher than in patients with skin metastases.