Background  Subungual squamous cell carcinoma (SSCC) is the most common malignancy of the nail unit. Mohs micrographic surgery (MMS) is a microscopically controlled surgical technique that has a high cure rate for skin cancers despite allowing narrow surgical margins.

Objective  To evaluate the long-term effectiveness of MMS in the treatment of SSCC, and in particular its ability to reduce the number of digital amputations.

Methods  Fifteen patients diagnosed with SSCC were treated with MMS as the first-line surgical approach, and were followed up for between 2 and 5 years.

Results  SSCC was completely excised in 13 patients, while two patients required amputation of the distal phalanx. For tumours with predominantly exophytic growth, clinical and radiological findings were found not to be reliable indicators of bone invasion. No recurrences were detected on follow-up.

Conclusion  Our results show that MMS provides a high cure rate for SSCC and reduces the number of amputations needed. MMS should become the first-line surgical approach for SSCC.