The thesis deals with the differences between Female-to-Male (FtM) and Male-to-Female (MtF) transsexuals, focusing on their intelligence and personality traits. The aim of the study was to compare the results between male and female transsexuals in these two areas and to recognize if the distribution of given personality traits corresponds more to their biological sex or to the gender identity. In the theoretical part of the work, studies about males and females in the population are presented and put into a broader context of the studies concerning FtM and MtF transsexuals, while using all accessible literature. The research comprises of data comparison of 200 transsexuals (100 MtF and 100 FtM) using Raven's Progressive matrices and DOPEN questionnaire. The results were evaluated by the statistical analysis and were later compared to the norms for men and women in population. There were found no differences in intelligence in both groups of transsexuals. Both groups' intelligence (IQ 117) is slightly above-average. Using the Raven's Progressive matrices, higher variability of results was measured in the MtF group. Male-to-Female transsexuals reached significantly higher scores in neuroticism compared to Female-to-Male group. This scale was identified as significantly higher in both groups when...