Malignant melanoma is a neoplasia that has its origin in the melanocytes, the melanin-synthesizing pigment cells present in the epidermis or sometimes in the dermis. Sentinel lymph node biopsy (SLNB) is the standard procedure used for staging patients with malignant melanoma in the majority of surgical centers in the world. With a probability of approximately 20% of finding positive lymph nodes, it spares a large number of patients of a complete lymphatic dissection. The aim of this study is to evaluate the factors that can predict the positivity of sentinel lymph nodes in malignant melanoma patients. We performed a retrospective study analyzing the histopathologic reports of patients who underwent SLNB for malignant melanoma between 2012 and 2015. There were 32 patients identified, out of which only three (9.37%) had positive SLN, so the majority of our patients were spared of regional lymphatic dissection. In our series, lymphatic invasion (p = 0.01), Breslow index >4 mm (p = 0.0064), AJCC staging (p = 0.0008), the presence of precursory lesions (p = 002), and microsatellitosis (p = 0.017) were predictive factors for the positivity of the SLN in malignant melanoma patients. Although our results are similar to those published in the literature, we consider that larger cohort studies should be performed to consolidate our results.