The intravesical instillation of lidocaine solution has been used as a topical form of anesthesia for bladder biopsies. We performed 63 ambulatory procedures in which multiple cold-cup biopsies were obtained during cystoscopy. There was no need for electrocautery. All patients tolerated the procedure well and were discharged from the office immediately thereafter. There were no changes in heart rate or blood pressure during the procedures. Serum concentrations of lidocaine were measured in 10 patients at 5, 10 and 30 minutes, and they were clinically insignificant. This simple office procedure can be used for the diagnosis and followup of patients with carcinoma in situ of the bladder.