Objectives: To report a series of patients with mucinous (colloid) adenocarcinoma (MC) at prostatectomy who were treated at a single institution from 1987 to 2005. MC is a rare form of prostate cancer reported in some cases to have a more aggressive clinical course than conventional adenocarcinoma (AC). Methods: Radical prostatectomy specimens with mucinous features were identified from a database of 3613 consecutive patients. Each case was reviewed again by a single pathologist who confirmed the diagnosis of MC in 14 patients. MC was defined by the presence of pools of extracellular mucin in more than 25% of the tumor. Eighteen additional cases were identified in which the mucinous component occupied only a small portion of the tumor and were referred to as AC with focal mucin (AFM). The biochemical and overall survival of 26 patients with MC or AFM who had completed ≥6 months of follow-up was analyzed using Kaplan-Meier estimates. Results: No patients with MC or AFM died of disease, and 11 (91.7%) of 12 patients with MC and 9 (64.3%) of 14 patients with AFM were clinically and biochemically free of disease. No significant difference was found in biochemical recurrence or overall survival between those with MC or AFM and a matched group of patients with AC. Conclusions: We report what we believe to be the largest published series of cases of MC (n = 14) with a median overall follow-up of 6.4 years. MC appears to behave clinically in a similar fashion to AC, with no statistically significant difference in biochemical failure or survival. © 2006 Elsevier Inc. All rights reserved.