Despite the high prevalence of posttraumatic stress disorder (PTSD) and medical comorbidity among veterans from Iraq/Afghanistan (OEF/OIF), keeping these patients engaged in health care is challenging. Primary Care-Mental Health Integration (PC-MHI), an initiative in the Veterans Health Administration (VA), sought to improve access to mental health care from within primary care. This study examined the lag between first PC-MHI visit and next mental/medical care visit, if any, and the relationship of PC-MHI with short-term (subsequent year) and long-term (4 years later) use of VA. We identified 2,470 OEF/OIF veterans receiving care during fiscal year 2006 (FY06) in a regional VA health care system. Unconditional survival analysis modeled time to next mental/medical visit and logistic regression modeled short- and long-term care as a function of PC-MHI, demographics, and clinical covariates. Of 181 patients in the PC-MHI program, 60%/18% returned for mental/medical care within 1 month, and 82%/74% within 1 year. Sixty-one percent (1,503) were still using the VA in FY09. Short-term mental care was related to prior-year PC-MHI. Consistent correlates of short- and long-term mental/medical care included physical comorbidity and Priority 1 status. Most patients attended mental health appointments subsequent to PC-MHI, and PC-MHI was correlated with mental health treatment retention in adjusted models for our cohort. Need for treatment, notably VA Priority 1 status and physical comorbidity, were the primary correlates of care-seeking. Developing innovative approaches to engaging new veterans in care remains imperative as multiple options will be necessary to meet the needs of these complex patients.