In an attempt to evaluate the prognostic factors for primary squamous cell carcinoma of the skin treated by conventional surgery, a 6 year (1990-1995) cohort comprising 171 patients was analysed. Of these 171 patients, 157 were confirmed as having been treated for invasive squamous cell carcinoma, of whom 64 (41%) died within 5 years of treatment from causes other than squamous cell carcinoma, and were therefore defined as indeterminate. The remaining 93 patients were determinate patients; 85 lived without recurrence or metastasis for at least 5 years after treatment, and eight died of their disease. Comparing the groups who were alive or had died of disease at 5 year follow-up, the tumour diameter and tumour thickness were significantly greater in the eight patients who died (P = 0.02 and P = 0.0057, respectively) but there were no significant differences between the two groups with regard to age, deep resection margin clearance, lateral epidermal resection margin clearance, lymphocyte response or degree of tumour differentiation. This study defines the 5 year follow-up outcome following conventional surgery for squamous cell carcinoma of the skin, related to histological parameters, which, if routinely reported, would allow valid comparisons to be made between differing primary therapies.