Background Duration of stay for coronary artery bypass graft operation outcomes differs for black versus white patients, with differences often attributed to insurance. We examined black versus white differences in duration of stay among TRICARE-covered patients undergoing coronary artery bypass graft. Methods Patients aged 18–64 years with TRICARE who underwent isolated coronary artery bypass graft (ICD-9CM 36.10–36.20) between 2006–2010 and who identified as black or white race were identified. Negative binomial regression, stratified by sex and military versus civilian facility, examined the duration of stay controlling for patient- and hospital-level factors. Results Of 3,496 eligible patients, 2,904 underwent coronary artery bypass graft at 682 civilian and 592 at 11 military hospitals. Patients (mean age 56.2 years) were predominantly white (88.9%), male (88.7%), married (88.2%), and retired (87%). Black patients demonstrated longer duration of stay (8.6 vs 7.5 days, P > .001), and overall duration of stay was longer at military facilities (8.1 vs 7.5 days, P = .013). Among the men, mean duration of stay was 14% longer for black patients at civilian hospitals (95% confidence interval 1.07–1.22) with no race-based differences at military facilities. Conclusion Among coronary artery bypass graft patients with TRICARE coverage, black, male patients demonstrated greater duration of stay at civilian facilities. Further work should examine care at military hospitals to elucidate factors that drive the apparent mitigation of race-related variability in duration of stay.