Masculine gender identity and its relationship with self-concept and psychological adjustment was studied for men with serious mental illnesses. Two hundred and thirty-eight men with serious mental illnesses from 15 psychosocial rehabilitation centers in Maryland and Northern Virginia rated a set of 47 masculine beliefs and attributes. Items were derived from a previous study (Keller, 1994) which generated a set of 78 beliefs about masculinity through a series of 9 focus groups with men in this population. Each of the 4 7 items in the present study was rated in terms of (a) how much each item was " like me" and (b) how important each item was to being a man. Test-retest correlations for the set of 47 items were r =.62 for ratings of how much "like me" items were and r =.92 for ratings of importance. Internal consistency (alpha) for the two sets of ratings were .93 and .94, respectively. Participants also completed (a) self-ratings of the words "masculine" and "feminine" (Spence, 1984) and (b) measures of psychiatric symptoms and psychological adjustment including the Brief Symptom Inventory, the Beck Depression Inventory, the Rosenberg Self-Esteem Scale, the Self-Efficacy Scale and the Internalized Shame Scale. Factor analysis of ratings for masculine beliefs and attributes revealed three dimensions (labeled morality, family, and toughness) which diverged from the patterns described in the general literature on masculinity. A cluster analysis based on factor scores for these dimensions failed to reveal subgroups of men distinguished by gender identity as defined through the factors. Degree of discrepancy between men's ratings of how much masculine beliefs and attributes were "like me" and ratings of the importance of those items to being a man was associated with higher global symptom severity (r =.21, p<.01), depression (r =.32, p<.01), and internalized shame (r =.26, p<.01), and with lower self-efficacy beliefs (r =.33, p<.01). Men who rated themselves as more masculine than feminine revealed significantly better adjustment, on the above measures, than men who rated themselves as neutral or more feminine than masculine. Divergence between the current factors and those from the general literature on masculinity, in terms of the dimensions of masculine beliefs and attributes found for this group of men, is discussed as a function of the losses and limitations inherent in the experience of serious mental illness. The inverse association between psychological adjustment and self-discrepancy on the set of masculine beliefs is presented as locus for further research and intervention.