Loneliness is common in dementia caregivers as cognitive impairment (CI) alters marital and social relationships. Unexplored is how an individual’s loneliness is affected at earlier, more ambiguous, periods of their spouse’s CI.Using the Health and Retirement Study, our study participants included 2,206 coupled individuals with normal cognitive function at the 2006/8 baseline. Loneliness outcomes at baseline, 4-year, and 8-year follow-up are assessed by the status of transition to cognitive impairment no dementia (TCIND) (2010/12 & 2014/16) using linear mixed models. Individual’s loneliness was stable when their spouse’s cognition remained normal, but increased with the spouse’s TCIND. The increase in loneliness did not vary by gender. Loneliness, a key risk factor for reduced life quality and increased depression, increases even at early stages of a partner’s CIND. This work suggests the potential impact of early intervention and social support for partners of individuals with CIND.