Introduction Transsexualism is a rare condition, characterized by permanent conviction of belonging to opposite sex, leading to a request for hormono-surgical sex reassignment. Objectives and aims of the study The personality of transsexual patient is a matter of debate: most psychoanalysts postulate a severe personality disorder, while STOLLER's and biological hypothesis argue for of the absence of specific disturbance. Methods Fourteen transsexuals patients (9 men and 5 women), referred to the specialized multidisciplinary team of Nantes University hospital were included. All received hormone therapy, 5 patients underwent surgery. The MMPI-2 and SCID-II were used as standardized tools to assess personality. Results Using the SCID-II, frequency of personality disorders was 14.29%, showing no statistical difference compared to the general population (10%). The MMPI-2 mean T score was close to the general population 50. Moreover, man versus woman transsexuals have a degree of psychopathology significantly higher than woman versus man transsexuals. Operated versus non-operated patients showed no significant differences in the various tests. Conclusion Our results tend to relativize the unique psychopathological determinism of transsexualism, and seem to strengthen the hypothesis of biological factors involved in this problem. The prognosis is more favorable for woman versus man transsexuals.