Although social scientists have long assumed that intimate social relationships are more closely associated with women's than men's mental health, recent research indicates that there are no gender differences in the advantages of marriage and disadvantages of unmarried statuses when males' and females' distinct expressions of emotional distress are considered. These findings have led to the conclusion that there has been a convergence in the importance of intimate relationships for men's and women's mental health. However, these patterns may not be evident for nonmarital romantic relationships among current cohorts of young adults. In this article, we examine the associations among several dimensions of these relationships and symptoms of both depression and substance abuse/dependence in a diverse sample of young adults in Miami, Florida. We find gender differences that vary across dimensions of relationships: While current involvements and recent breakups are more closely associated with women's than men's mental health, support and strain in an ongoing relationship are more closely associated with men's than women's emotional well-being. Our findings highlight the need to consider the period in the life course as well as experiences of specific cohorts of men and women when theorizing about gender differences in the importance of intimate relationships for mental health. (Contains 5 tables and 6 notes.)