Abstract Background The aim of this study was to compare the overall survival (OS) of different groups of AJCC 2002 stage III cutaneous melanoma patients and to prove that patients with positive sentinel lymph node (SN) are heterogenic group with very different survival rates. Methods A total of 325 patients with stage III melanoma were identified from the prospective melanoma database at the Institute of Oncology Ljubljana, Slovenia; 164 had delayed therapeutic lymph node dissection (DLND), 111 had a positive sentinel lymph node biopsy followed by completion lymph node dissection (CLND) and 50 had synchronous primary melanoma and regional lymph node metastases that were treated with radical excision of the primary tumor and therapeutic lymph node dissection (TLND). Univariate and multivariate analyses were used for the assessment of the factors associated with OS and for comparison of OS between different subgroups of patients. Results The worst 5-year OS had the patients with synchronous primary melanoma and regional lymph node metastases. The patients with SN metastases with a diameter of 5.0 mm or less had significantly better OS than those with DLND, while the patients with SN metastases with a diameter of more than 5.0 mm had similar survival to those patients with synchronous primary melanoma and regional lymph node metastases. Conclusion Melanoma patients within AJCC 2002 stage III group have very different survival rates. The group of patients with positive SN is also prognostically heterogenic because it contains patients that have better survival than those after DLND as well as patients with more aggressive disease, that have similar survival as those with synchronous primary melanoma and regional lymph node metastases.