To describe the relevant morphologic features and to create a simple diagnostic method for pigmented basal cell carcinoma (BCC) using in vivo cutaneous surface microscopy (ie, dermoscopy, dermatoscopy, or oil epiluminescence microscopy).Design: Pigmented skin lesions were photographed in vivo using immersion oil (surface microscopy). All pigmented skin lesions were excised and reviewed for histological diagnosis. Photographs of 142 pigmented BCCs, 142 invasive melanomas, and 142 benign pigmented skin lesions were randomly divided into 2 equally sized training and test sets. Images from the training set were scored for 45 surface microscopy features. From this a model was derived and tested on the independent test set.