Morphologically normal spermatozoa from groups of men attending the infertility clinic with normal density and motility had subcellular elemental composition measurements from various parts of the spermatozoa compared with anatomically similar spermatozoa from semen with marked oligo- or asthenozoospermia. In the two groups of semen the mean % value of the elements was similar in the acrosome, nucleus, mid-piece and tail regions excepting sodium and potassium which were significantly lower in the abnormal semen. Although a similar elemental distribution was found in each group the observed trend towards higher total values in the abnormal semen did not reach significance. Highest levels were found in the nuclear and mid-pieces of all spermatozoa suggesting future diagnostic possibilities for such measurements in determining spermatozoal procreative potential.