By means of cluster analytic techniques, four subtypes of psychosocial adjustment were identified in a sample of 122 breast cancer patients who completed the Psychosocial Adjustment to Illness Scale. Internal consistency and internal validity of the derived typology were suggested by the finding that two different hierarchical agglomerative clustering methods (average linkage between groups, Ward's) produced similar solutions. Three of the derived subtypes reported normal affect levels but different patterns of relative strengths and dysfunctions, while the fourth subtype appeared to be highly distressed and globally maladjusted. External validation was demonstrated by differentiating the subtypes on variables of negative affect, avoidance coping, and fighting spirit. The clinical and heuristic implications of these findings are discussed. The findings highlight the need for comprehensive assessment of psychosocial functioning of cancer patients. They demonstrate that even non-emotionally distressed patients can have very different profiles of adjustment and may benefit from correspondingly individually tailored psychosocial interventions.