['The aim of the study was to define the learning curve of a single cytologist as a limitation of urinary cytology. A total of 1034 cytologic and histologic findings of patients undergoing transurethral resection of the bladder for suspicion of bladder cancer were reviewed, and cytologic evaluations of a single cytologist from the beginning of his learning period were compared with the results of a cytologist at a national reference center. Our results showed that the individual learning curve has a significant impact on the quality of urine cytology.', 'To define the learning curve of a single cytologist as a limitation of urinary cytology and to compare his results with a reference center for urinary cytology.', 'Cytologic and histologic findings of patients undergoing transurethral resection of the bladder for suspicion of bladder cancer were reviewed. Cytologic evaluations from a single local cytologist during his learning period and of a cytologist of a national reference center were compared. Changes of sensitivity and specificity of cytology from the local cytologist over the time period were assessed. Differences were estimated by using kappa statistics.', 'The local cytologist evaluated 1034 cytologic findings. Sensitivity and specificity of cytology estimated by the local cytologist were 86% and 66% at the beginning of the learning period, but 68% and 84% at the end of it (P ≤ .05). In high-grade carcinomas, sensitivity did not decrease over the years (P > .05). In contrast, the sensitivity in the diagnosis of low-grade tumors decreased from 86% to 56% (P ≤ .05). The reference center estimated a constant sensitivity and specificity of 59% and 97%, respectively. Agreement of findings between local and national cytologists increased significantly over the learning period (P < .05).'] Does individual learning curve reduce the clinical value of urinary cytology?