To assess the diagnostic criteria for grade 1 papillary transitional cell carcinoma (TCC) in cystoscopically obtained urine. We compared the sensitivity, specificity and positive predictive value of cytologic, architectural and morphometric (primarily architectural) criteria in 177 specimens with corresponding biopsy follow-up. Sensitivities ranged from 22% to 44%, specificities from 69% to 85% and positive predictive values from 59% to 66%. The currently described cytologic, architectural and morphometric criteria are inadequate for the identification of grade 1 papillary TCC, and the cytologic diagnosis of grade 1 papillary TCC in cystoscopically obtained urine remains unreliable.