Background: Bladder and kidney cancers are the fourth and sixth most commonly occurring cancers among men in the United States. The risk of these urologic cancers, however, may differ among U.S. servicemen compared to general population men. To date, bladder and kidney cancer rates among men in the military have not been systematically studied, thus, this study compared incidence rates and trends of bladder and kidney cancers between active-duty servicemen and men in the general US population. Methods: Data were obtained from the Department of Defense’s Automated Central Tumor Registry (ACTUR) and the National Cancer Institute’s Surveillance, Epidemiology and End Results (SEER) database. The analyses included men aged 18–59 years in ACTUR and SEER who were diagnosed with invasive bladder and kidney cancers from 1990-2013. Active-duty population counts were sourced from the Defense Manpower Data Center. General population counts were sourced from SEER. Age-adjusted incidence rates per 100,000, incidence rate ratios (IRR), and their 95% confidence intervals (95% CI) were calculated. Population comparisons were further made by race (White, Black, Other), age (18-29, 30-39, 40-49, 50-59 years), and cancer stage (local, regional, distant). Joinpoint regression analysis was conducted to examine temporal cancer incidence trends for each population. Results: Between 1990 and 2013,257 diagnoses of bladder cancer and 581 diagnoses of kidney cancer were recorded among men in ACTUR. The corresponding numbers were 17,449 and 17,808 in SEER. Overall, age-adjusted incidence rates were lower in ACTUR than SEER for bladder cancer (IRR=0.55, 95% CI=0.48-0.62) and marginally lower for kidney cancer (IRR=0.92, 95% CI=0.84-1.00). Incidence rates of bladder cancer were lower in ACTUR than in SEER among both Black and White men whereas rates of kidney cancer were only lower in ACTUR among Black men. Differences by age in bladder cancer incidence were only observed among 18–49-year-old men. For kidney cancer, incidence was lower in ACTUR only among 30–49-year-olds. Rates by tumor stage were lower in ACTUR than SEER for local and regional bladder cancers. Between 1990 and 2013, bladder cancer incidence rates decreased in both populations, but rates in ACTUR (average 3-year percent change (3PC)= -16.7) decreased more than rates in SEER (3PC= -6.1). Kidney cancer incidence trends were statistically equivalent between populations; rates were stable from 1990-1998 but increased from 1999-2013 (3PC= 16.6 ACTUR and SEER). Conclusions: Bladder and kidney cancer incidence rates among men were significantly lower in the active-duty than the general population. Lower bladder and kidney cancer incidence in ACTUR, notably in younger individuals, may reflect the healthier status of servicemen who receive free and mandatory medical care. The lack of differences in bladder or kidney cancer incidence among men aged 50-59 might reflect more cumulative military-related exposures to risk factors among those who have served the military longer, which might have countered the effects of healthier status in the military. This study highlights the need for further research to better explain variations in urologic cancers among men between these populations.  Disclaimer: The contents of this publication are the sole responsibility of the authors and do not necessarily reflect the views, opinions, or policies of the Uniformed Services University of the Health Sciences (USUHS), the Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., the Department of Defense (DoD) or the Departments of the Army, Navy, or Air Force. Mention of trade names, commercial products, or organizations does not imply endorsement by the U.S. Government.