In a previous study we found allelic imbalances of Rb and L-myc associated with disease stage and disease course in bladder cancer. The primary aim of the present study was to determine whether the changes found in tumors were reflected in urine sediments. Secondly we wanted to test if Rb and L-myc were frequently lost in urine sediments from patients with carcinoma in situ and no bladder tumor at present. Based on this we examined allelic deletions of the Rb and L-myc genes in tumor and urine from 55 patients with bladder tumors or carcinoma in situ. Deletions were examined on extracted DNA from tumors and urine sediments by the use of microsatellite markers located as close to the genes as possible. Fifty-five patients and 10 controls were included. We found no strict correlation between allelic deletions in bladder tumors and urine sediments from the same patient. Allelic deletions in urine sediments were at least as common in patients with carcinoma in situ and no bladder tumor (32%) as in patients with bladder tumors (20%). It was possible to identify allelic deletions in urine sediment from 1 patient with cystitis and no history of malignant bladder disease (6%). In conclusion we found no strict correlation between allelic deletions in bladder tumors and urine sediments. Allelic deletions in urine sediments seem to be at least as common in patients with carcinoma in situ as in patients with bladder tumors.