Abstract: Despite effective psychotherapy options for posttraumatic stress disorder (PTSD), some patients do not fully respond, and even among those reporting substantial improvement, residual symptoms following treatment are common. Psychiatric conditions frequently co-occur with PTSD, yet research on residual symptoms among comorbid samples is lacking. This study examined residual symptoms of PTSD and depression among 71 active duty service members with PTSD and comorbid major depressive disorder (MDD). As part of a clinical trial, participants were randomized to cognitive processing therapy (CPT) or a novel treatment designed to address PTSD and comorbid MDD, behavioral activation-enhanced CPT (BA + CPT). Analyses compared individual residual symptoms between treatments and groups based on PTSD and MDD diagnostic status at posttreatment. For both PTSD and MDD, the conditional probabilities for each residual symptom did not differ between CPT and BA + CPT, suggesting treatment type did not influence which symptoms persisted. For the 36 service members who lost their PTSD diagnosis at posttreatment, conditional probabilities of residual PTSD symptoms were highest for sleep problems, concentration difficulties, and hypervigilance; for MDD symptoms, conditional probabilities were highest for sleep problems, concentration difficulties, and low energy. These most common residual symptoms were identical for the 31 service members who lost their MDD diagnosis at posttreatment. Residual symptoms observed among service members with PTSD and comorbid MDD mirrored those commonly identified among single disorder PTSD or MDD samples. Identifying and addressing residual symptoms most meaningful to patients will maximize benefit from PTSD treatment.