Methods: This trial recruited 837 subjects from 6 PTSD residential treatment programs at 5 VA medical centers, 94.7% of the 884 projected. Patients who completed at least 14 days of residential PTSD treatment and discharged to VA outpatient care were eligible to participate. Subjects were randomized to usual aftercare care (n = 425) or usual aftercare plus biweekly telephone case monitoring calls during the first three months after discharge (n = 412). Telephone case monitors assessed current problems, encouraged treatment adherence, provided problem-solving support, and alerted providers to emergent care needs. Patient self-report measures of psychiatric symptoms, substance use, and violence were obtained at intake to residential treatment and 4 months (69% completion rate) and 12 months (64% completion rate) after discharge. Retention was lower than the investigators' planned 70% to 75% rate due to difficulty locating some patients who moved (even their collateral informants did not know where they were) and 45 participants asking to discontinue due to lack of time (n = 10), general dissatisfaction with VA (n = 6), distress during phone calls (n = 5), dissatisfaction with compensation (n = 1), or no specified reason (n = 24). Treatment utilization data was obtained from the VA National Patient Care Database.