The relationship between tumour proliferative activity, evaluated by thymidine labelling index (TLI), clinicopathological variables and clinical outcome, was analysed in a series of 64 chemotherapy-resistant, ovarian cancer patients. The median TLI of 4.6\% (range 0.01-45.7) was used as the cut-off to discriminate rapidly from slowly proliferating tumours. Univariate analyses showed a significant advantage in survival for patients with TLI less than or equal to 4.6 (P = 0.0004), ECOG performance status less than or equal to 1 (P = 0.0001) and residual disease after primary surgery less than or equal to 2 cm (P = 0.019). Multivariate analysis demonstrated that performance status was the only independent prognostic variable, although TLI was the last covariate removed from the Cox's regression model