Abstract: Objective To evaluate the role of prophylactic regional lymph node dissection (LND) in the management of primary malignant melanoma. Methods 56 patients with WHO clinical stage Ⅰ malignant melanoma in the extremity, who had no palpable regional lymph node, were randomly divided into two groups. There were 30 patients in LND group who underwent excision of primary tumor plus LND, whereas 26 patients in control group who underwent excision of primary tumor alone. The excisions of primary tumor for two groups were the wide resections with a margin of at least 2 cm. All patients had the same modality of adjuvant therapy after operation. The overall survival rates for the 2 groups were estimated with the Kaplan-Meier method and the survival curves were compared using the log-rank test. Results The median follow-up for all patients was 43.5 months (range, 11～84 months). The five-year overall survival rates were 64.79% for LND group and 33.68% for control group, respectively. The Log-rank test (P=0.0414) showed that there was a statistically significant difference between the two groups. Conclusion Prophylactic regional lymph node dissection may improve the survival rate of surgical management for patients with WHO stage Ⅰ malignant melanoma in the extremity.