Objective: To review atypical/positive urine cytology specimens from patients with confirmed prostatic duct adenocarcinoma (PDA), describe the cytomorphologic features and discuss the differential diagnosis. Study Design: A retrospective review of the cytopathology archives of The Johns Hopkins Hospital revealed 14 cases of abnormal urinary cytology in patients with histologically confirmed PDAs. Cytologic material was reviewed; cytomorphologic characteristics were analyzed and correlated with histopathologic features wherever possible. Results: There were 7 patients ranging in age from 52 to 80 years (mean age: 68 years). The clinical presentation included; hematuria, bladder obstruction and perineal mass. The cytomorphologic characteristics were: large crowded sheets and three-dimensional fragments (some with papillary architecture) of columnar epithelium with scant amphophilic cytoplasm, basally placed round to oval nuclei with coarse chromatin and absent or inconspicuous nucleoli. Histologic findings showed papillary and cribriform architecture of columnar cells with crowding, nuclear stratification and overlapping with or without nucleoli. Conclusion: PDAs usually present at an advanced clinical stage and may exfoliate owing to their location in the central prostatic urethra. Differentiating PDA from acinar prostatic adenocarcinoma, urothelial carcinoma and metastatic adenocarcinoma is important due to the differences in patient management. Since prostate-specific antigen values are variable, urine cytology may provide a valuable tool for the early detection of these aggressive lesions.