Background: In the regional setting, general practitioners often refer complicated skin excisions to general surgery, whereas in larger centres this is the domain of plastic surgery. General surgical trainees often do not have adequate exposure to complex skin excisions prior to placement in regional centres. Objective: To explore what factors affected positive margin rates in surgical registrars in a regional setting. Design: Retrospective audit. Setting: Large teaching hospital (referral centre). Participants: All skin lesions excised under local anaesthetic by registrars at a single referral centre over a 30-month period from 2007 to mid 2009, of these only basal cell carcinomas (BCC) and squamous cell carcinomas (SCC) were analysed. Results: Registrars excised a total of 703 skin lesions, 314 (43.4%) were BCC or SCC, and of these 50 (15.9%) had positive margins. Repeated measures multivariable logistic regression was performed on relevant data. Surgical registrars had significantly higher positive margin rates when operating unsupervised (P=0.014). Although not significant, there was a tendency for BCC excisions to have positive margins (P=0.059). There was no statistical difference when comparing lesions excised on the head compared to body, use of a graft/flap or registrar training level. Conclusion: This study's positive margin rate of 15.9% falls within the range reported in the literature (0.7% to 20.7%); however, this has the potential to be further reduced. Surgical registrars excising skin lesions in regional centres, regardless of level of training, should have closer supervision. Regular surgical audit should be done so registrars can have early feedback on performance.