The authors assessed during comprehensive examination of amniotic fluid obtained by transabdominal amniocentesis on account of genetic indication during the second trimester of normal pregnancy between the 15th and 22nd week of gestation four selected trace elements - Zn, Cu, Pb and Cd, using the method of atomic absorption spectrometry. One of the criteria for evaluation of the results was also the relationship of the concentration of the selected trace elements and sex of the foetus. In 157 amniotic fluids collected during the 16th-19th week of gestation they recorded a significantly elevated lead level in male foetuses. During the 17th week normal pregnancy they found also a significantly increased zinc concentration in amniotic fluid of female foetuses. The authors are so far unable to interpret these interesting results which will be the subject of future investigation.