Dermatoglyphic analyses were carried out on a sample of children with known sex chromosomal aneuploidies (25 XXY, 10 XXX, 1 XXYY). Digital ridge counts and pattern types were determined for each individual. Palm prints and sole patterns were also examined. The results of our study were compared with data from previous studies of sex chromosomal aneuploidies. Our results for the XXY males agree with the findings from other studies with respect to total ridge counts and plantar dermatoglyphics, but not for digital pattern frequencies. Our one example of an XXYY male showed hypothenar patterns similar to those found for this syndrome by other researchers, but neither the digital pattern types nor the unexpectedly high total ridge count conforms to the findings from other studies. Our sample of XXX females falls within the normal XX female range of variation with respect to hypothenar patterns and total ridge count; plantar features show a higher incidence of patterns than previously reported.