In this study we investigated the relationship between personality attitudes, psychopathological symptoms and biological parameters in male infertility. Eighty-four infertile men underwent a psychological and medical examination at our clinic. The psychological tests comprised the Symptom Checklist 90-R, the Toronto Alexithymia Scale and the NEO-Five Factor Inventory. Seminal parameters, gonadotrophins, sex steroids, cortisol and prolactin were analyzed to obtain biological data. Compared with questionnaires completed by normal populations those in the study group scored higher on the scales for 'conscientiousness', 'agreeableness', 'alexithymia' and 'somatization' and lower on the scale for 'neuroticism'. Regarding psychobiological correlations we found a negative correlation between seminal parameters and 'extraversion', 'anxiety' and 'psychoticism'. 'Alexithymia' was negatively correlated with stress hormones and 'conscientiousness' was correlated with sex steroids. The findings suggest above average social competence in the study group. The psychobiological correlations indicate a link between social-competence-related personality traits such as 'extraversion' and 'conscientiousness' and biological fertility characteristics. Implications of a higher alexithymia in infertile men, which is negatively correlated with stress hormones, are discussed.