This application is a joint submission of the War Related Illness and Injury Study Center (WRIISC), The Polytrauma Network Site (PNS) and the VISN 21 Mental Illness Research, Educational and Clinical Center (MIRECC) at the VA Palo Alto Health Care System. One of the major post-deployment health concerns that the WRIISC & PNS are focusing on is Traumatic Brain Injury (TBI). The VISN 21 MIRECC has a long research history addressing sleep disorders in Veterans including several research projects on insomnia in Veterans. In recent years over 650 VA mental health clinicians have been trained in CBT-I by the VISN 21 MIRECC. The proposed collaboration between WRIISC, PNS and MIRECC will evaluate the efficacy of Cognitive Behavior Therapy for Insomnia (CBT-I) in TBI Veterans with chronic insomnia in a randomized controlled trial. CBT-I has been suggested to be a good alternative to pharmacological approaches in the treatment of TBI patients with insomnia but evidence to support this claim is lacking. This trial will compare CBT-I with a previously used manualized active control condition called “Credible Control Therapy for Insomnia” (CCT-I) in mild TBI (mTBI) patients suffering from insomnia. Like many previous control conditions in randomized controlled trials CCT-I includes a sleep hygiene component. Our hypotheses will be tested in a randomized controlled clinical trial. The randomization will be stratified by potential comorbidity of current Post-Traumatic Stress Disorder (PTSD) and use of sleep medications. After screening and randomization in the 2-week baseline phase, subjects will receive either CBT-I or CCT-I in the 6-week treatment phase. This 4-year proposal will include 120 mTBI patients (2 groups of n=60 each) with relevant measures collected at baseline, week 8 after treatment and week 32 for follow-up. The primary outcome will be the Insomnia Severity Index. The secondary outcome will be the SF 36-Item Health Survey.