This study considers whether socioeconomic status influences the impact of social isolation on mortality risk. Using data from the Alameda County Study, Cox proportional hazard models indicate that having a high income worsens the mortality risk of social isolation. Education may offset risk, however, and the specific pattern that emerges depends on which measures for socioeconomic status and social isolation are included. Additionally, lonely people who earn high incomes suffer especially high risk of accidents and suicides as well as cancer. Further research is needed that contextualizes the health risks of social isolation within the broader social environment.