We examined the effect of incisional biopsy on the subsequent histology of 15 benign melanocytic naevi. In all cases the histology of the residual lesion within the second specimen was unchanged apart from the presence of a surgical scar, and in general the definitive excision specimen showed a reduction in melanocytes at the dermo-epidermal junction overlying the scar. In no case were there any features suggestive of melanoma.