The efficacy of cultured keratinocyte allografts on the healing rate and pain relief of 30 small and medium-sized chronic venous leg ulcers was assessed in a prospective, randomized, placebo-controlled study. Measurements of surface area, ulcer bed appearance and pain severity were made at fortnightly intervals for 6 weeks. There was significant healing of ulcers in both the allografted and control groups (P= 0.001), but there was no significant difference between the two groups (P>0.05). There was also no significant difference between the two treatments in the amount of pain relief obtained. Thus, a single application of cultured keratinocyte allografts to chronic venous ulcers offered no advantage for wound healing or pain relief as compared with placebo. The low efficacy and the expense of cultivating and storing allografts does not allow a single application of cultured allografts to be recommended at present as a routine treatment for venous leg ulcers.