Summary Background Sentinel lymph node biopsy (SLNB) is usually performed using a triple technique that includes lymphoscintigraphy (LSG), which involves the injection of a radiolabelled tracer, blue dye injection, and detection of the radioisotope with a gamma probe. However, blue dye injection may cause pathological misinterpretation and obscure clinical margins, especially when combined with Mohs micrographic surgery (MMS) for cutaneous melanoma. Objectives To assess the efficacy of SLNB without blue dye injection in patients who subsequently underwent MMS for melanomas of the lower extremities. Methods We evaluated patients who underwent MMS with or without SLNB using preoperative localization of the primary melanoma via LSG and intraoperative confirmation using a gamma probe between 2010 and 2016. Results Seventy‐two patients with melanoma of mean Breslow thickness 3·03 ± 1·44 mm were evaluated. Sixty‐five of the 72 patients underwent SLNB, the success rate of which was 98%. The 5‐year overall and disease‐free survival rates were 78% and 76%, respectively. Conclusions Blue dye injection can be omitted without compromising the accuracy of standard SLNB. Omitting blue dye injection also has marked advantages in MMS for melanoma. What's already known about this topic? Sentinel lymph node biopsy (SLNB) is usually performed using a triple technique including lymphoscintigraphy, which involves the injection of a radiolabelled tracer, blue dye injection, and radioisotope detection using a gamma probe. Blue dye injection may cause pathological misinterpretation and obscure clinical margins. What does this study add? Omitting the dye does not decrease diagnostic accuracy and is particularly advantageous for Mohs micrographic surgery (MMS) in melanomas with clinically indistinct tumour borders. SLNB without blue dye injection is feasible in MMS for melanoma.