Background: Detrusor muscle at diagnostic transurethral resection of a bladder tumor (TURBT) is often used as a surrogate of resection quality. We examined whether surgical and pathologic quality at the time of initial resection was associated with improved cancer-specific survival among subjects diagnosed with non-muscle-invasive bladder cancer. Methods: We retrospectively reviewed the operative and pathology reports of all individuals ≥18 years of age within the Los Angeles SEER registry, with an incident diagnosis of urothelial non-muscle-invasive bladder cancer between 2004-2005. We recorded patient age, gender, race, marital status, socioeconomic status, insurance type, institution type, surgeon and pathologist volume, tumor stage and grade, detrusor muscle presence/mention, and vital status. After adjusting for confounding using competing-risks regression analysis, we determined whether surgical and pathologic quality was associated with cancer-specific survival. Results: We identified 1,865 patients, 335 urologists, and 278 pathologists. Muscle was reported as present in 972 (52.1%), reported as absent in 564 (30.2%), and was not mentioned in 329 (17.7%) of the initial pathology reports. The incidence of detrusor muscle sampling did not differ according to grade or stage. However, bladder cancer death was more likely with higher stage disease (Tis: HR=5.00, 95% CI 2.38-10.50; T1: HR=5.44, 95% CI 3.00-9.88) and lower quality staging (muscle absent: HR=1.50, CI 1.00-2.27; muscle not mentioned: HR=2.01, CI 1.14-3.56). This pattern was enhanced among those with high-grade disease. For this group, the 5-year cancer-specific mortality was 8.0%, 13.0%, and 21.5% when muscle was present, absent, or not mentioned, respectively. Conclusions: Nearly half of all diagnostic TURBTs do not include muscle. This omission is associated with increased mortality, particularly in high-grade disease—yet few of these patients undergo treatment to correct this error. Because urologists cannot discern between high- or low-grade disease, we contend that all patients with bladder cancer should undergo endoscopic resection with detrusor muscle sampling (and appropriate pathology reporting) at diagnosis.