Abstract: STUDY OBJECTIVES: This study evaluated the prevalence and correlates of insomnia in male Veterans with MST who currently receive care within a VAMC. METHODS: We evaluated cross-sectional data from a VAMC (N=138) using the following instruments: ISI, PCL-5, QIDS-SR, AUDIT-C, and a nightmare question for insomnia, PTSD, depression, and drinking, respectively. Bivariate and multivariable analyses assessed the relationship between ISI and other clinical variables. RESULTS: About 31.9% screened positive for MST. When compared to those without MST (MST-), those with MST (MST+) had a higher prevalence of insomnia (95.5% vs 81.9%), higher ISI (20±5.1 vs. 16.7±7.2, p=0.003) and PCL-5 (48.5±14.4 vs. 38.2±19.8, p=0.0008) total scores. In the multivariable models, the ISI total score was associated with the PCL-5 total score (p=0.015) in MST+ individuals and with QIDS-SR (p<0.001) in MST- individuals. CONCLUSIONS: Most Veterans with MST within the VHA had insomnia, which was associated with their underlying psychiatric comorbidity.