['The aim of this study was to examine the role of sentinel lymph node biopsy (SLNB) on long-term disease outcome in patients with intermediate-thickness primary cutaneous melanomas.', 'Forty patients with intermediate-thickness melanomas, defined as 1.0-4.0 mm, underwent SLNB between 1998 and 2011. The disease-free survival (DFS), overall survival (OS) and prognostic factors were analyzed.', 'Median age was 53 years (range: 24-74 years). Median Breslow thickness was 2.8 mm (range: 1.0-4.0 mm) and 27.5% were ulcerated melanomas. Median follow-up time was 70 months (range: 23-168 months). The number of patients with sentinel lymph node (SLN)-positive was 9 (22.5%) and completion lymph node dissection was performed in all of these patients. Ten patients (25%) developed distant and locoregional recurrence; 4 in the SLN-positive group (4/9; 45%) and 6 in the SLN-negative group (6/31; 19%), P < 0.042. In the SLN-negative group, one patient developed regional node recurrence; false-negative rate was 10%. SLN positivity and ulceration were independent prognostic factors for DFS in multivariate analysis (hazard ratio [HR] of 4.6, and 10.5, respectively; P < 0.011). For OS SLN positivity, ulceration and Breslow thickness were found to be the significant prognostic factors (HR of 5.4, 8.5 and 5.0, respectively; P < 0.024). Ten-year DFS and OS for SLN-negative and SLN-positive patients were 71%, 47% (P < 0.003), and 80%, 55% (P < 0.005), respectively.'] Does sentinel lymph node status affect long-term survival in patients with intermediate-thickness melanoma?