While chemotherapy offers a valuable adjunct to surgery in the management of intravesical bladder cancer, an accurate in vitro predictive test for chemosensitivity has yet to be developed. Drug sensitivity of the human bladder cancer cell line J-82 was assessed using monolayer, stem cell and [3H]thymidine incorporation assays. The 72-h monolayer assay provided a rapid reflection of in vitro drug sensitivity and when combined with the labeling index the results generally paralleled those obtained with the soft agar stem cell assay without the associated large commitment of time and labor. It is suggested that 72-h monolayer assay alone or in combination with [3H]thymidine labeling index may offer valuable insight into the chemotherapeutic response of bladder tumors.