ABSTRACT Introduction Karyotyping is often performed in transsexual individuals. Aim Quantification and characterization of karyotype findings and abnormalities in transsexual persons. Main Outcome Measures Karyotypes were listed both in male-to-female and in female-to-male transsexual persons. Methods The data were collected through a retrospective study. Results Karyotypes of 368 transsexual individuals (251 male-to-female, 117 female-to-male) are described. Normal findings were found in 97.55%. Prevalence of abnormal karyotypes was 3.19% among male-to-female, and 0.85% among female-to-male transsexuals. Nine karyotypes showed variations; Klinefelter syndrome was confirmed in three persons, whereas others displayed autosomal aberrations. Conclusion Karyotyping is only of very limited information in the transsexual population.