Benefits of relational intimacy on health may derive from its influence on the success of verbal attempts to motivate romantic partners' compliance with suggested protective behaviors. The intimacy levels of 209 participants' romantic relationships were assessed, as were motivations to change 4 health behaviors in response to 8 appeal strategies. Intimacy had significant impacts on the estimated effectiveness of several appeals. Also, as intimacy increased, caring replaced the provision of health information as the most efficacious strategy for motivating dietary modification. Overall, appeals seeking safer sex and those employing liking, caring, and threat strategies were rated as generally most effective.