To evaluate acute and long-term urinary morbidity after permanent prostate brachytherapy at a single tertiary care center. To minimize the risk of long-term urinary morbidity, it is important for clinicians to be able to distinguish acute urinary side effects after prostate brachytherapy from longer-term treatment-related urinary complications. The medical records of 351 consecutive patients who underwent prostate brachytherapy at the MD Anderson Cancer Center between 1998 and 2006 were analyzed. To evaluate the short-term urinary side effects, the Expanded Prostate Cancer Index Composite questionnaire was administered at baseline and at 1, 4, 8, and 12 months. Long-term urinary complications were scored using a modified Radiation Therapy Oncology Group scale. All 4 urinary subdomain scores evaluating acute urinary side effects after treatment (bother, function, incontinence, and irritation or obstruction) had returned to baseline levels by 8 months after implantation. At 5 years, the cumulative risks of late urinary complications by grade were 8.6% for grade 1 complications, 6.5% for grade 2, 1.7% for grade 3%, and 0.5% for grade 4. The most common grade 2 late urinary complications were urethral stricture (4 patients), incontinence requiring daily pads (3 patients), and intermittent hematuria (3 patients). Grade 3 complications were urinary retention requiring self-catheterization (2 patients) and severe frequency with dysuria (2 patients). The only grade 4 event was severe hemorrhagic cystitis. Short-term urinary side effects after prostate brachytherapy are common, follow a predictable course, and typically resolve within 1 year. Conservative management of short-term urinary side effects is recommended to minimize the risk of long-term urinary complications.