Fas (factor of apoptosis stimulus) is one of the death receptors belonging to the tumour necrosis factor superfamily of receptors. When bound to its ligand, Fas-ligand (Fas-L), it triggers apoptosis. Ultraviolet rays (UV rays) can induce keratinocyte apoptosis by Fas/Fas-L interaction. The expression of Fas and Fas-L in various skin diseases has been discussed before in some studies but still needs some clarification. The aim of the present study was to evaluate the role of Fas and Fas-L in one of the UV-induced skin tumours, namely basal cell carcinoma (BCC) and one of the UV-induced relatively benign skin disorders that could turn malignant, namely discoid lupus erythematosus (DLE). The study included 20 cases of BCC, 20 cases of DLE and ten control cases. All biopsies of BCC and DLE were examined histopathologically. They were also examined for Fas and Fas-L by PCR. Regarding the histopathological results of cases of BCC, apoptosis was detected in 12 out of the 20 cases (60%). Fas was found to be positive in only one case (five percent) and it was found to be negative in the other 19 cases (95%). Fas-L was found to be positive in all 20 cases of BCC studied (100%). In cases of DLE, apoptosis was detected in 18 out of the 20 cases (90%). Fas was found to be positive in 16 out of 20 cases (80%), while Fas-L was found to be positive in 18 out of the 20 cases studied (90%). As a conclusion, it seems that tumour cells of BCC have created an optimal regional immunosuppressive environment. Over-expression of Fas-L and lack of expression of Fas by tumour cells together with other factors act in favour of BCC by helping its survival and progression. Also, taking into consideration the results of the present study regarding cases of DLE, it seems that Fas/Fas-L interaction plays a critical role in the apoptosis seen in cases of DLE and hence in the pathogenesis of DLE. Another important finding, detected in the present study, is that the extent of apoptosis was found to be statistically higher in cases of DLE than in cases of BCC, which may indicate that apoptosis is considered to be a protective factor against the development of carcinogenesis.