OBJECTIVE The implantable cardioverter defibrillator (ICD) is the treatment of choice for prevention of sudden cardiac death. However, a subgroup of ICD patients experiences psychological adjustment problems post implant. To date, positive psychological constructs (e.g. optimism) have been understudied in this population. Hence, we examined the association between optimism and anxiety, depression, and health status at 12-months post implant. METHODS Patients (N=171) enrolled in the WEB-based distress management study for ICD patients were included in the analyses. Optimism and pessimism (LOT), and Type D personality (DS14) were administered at baseline, while anxiety (GAD-7), depression (PHQ-9), and health status (SF-12) were assessed at 12-months. RESULTS The mean age was 59.6±10.06 with 81% being male. After controlling for demographic, personality, and clinical variables, baseline optimism was associated with lower anxiety (β=-0.210; p=0.011) and depression (β=-0.222; p=0.005), and better physical (β=0.227; p=0.004) and mental health status (β=0.350; p=0.000) at follow-up. Optimism was also associated with change in mental health status (β=0.195; p=0.007) but not with change in anxiety, depression, and physical health status at follow-up. CONCLUSIONS Our findings indicate that optimism is associated with less distress and possibly helps safeguard mental health in ICD patients. Increase optimism might be the way forward to reduce long-term distress and impaired health status. TRIAL REGISTRATION http://www.ClinicalTrials.gov. Identifier: NCT00895700.