The purpose of this cohort sequential study was to determine whether the presence of complicated grief (CG) measured at various points in the spousal bereavement process is associated with an increase in mental and physical health problems 18 months later. One hundred twelve participants provided data at four points in time. CG was measured with the Inventory of Complicated Grief (ICG), and mental health was measured with the Integra Outpatient Tracking Assessment, Mental Health Index (MHI), and illnesses by self-report. Twenty-nine participants were identified as experiencing CG. Beginning at 6months after the death, MHI scores were significantly lower for the CG group and those results were persistent. The CG group experienced more additional life stressors, perceived less social support, and achieved less clinically significant change in MHI than the NCG group. Identification of CG at any point at 6 months or later in bereavement indicates a need for professional intervention. Implications for establishing CG as a DSM diagnosis are discussed.