The increase of growth hormone expression in pigs transgenic for WAP-hGH gene construct of F3 (non-pregnant and lactating sows) and F5 generations (young gilts in age of 5 and 9 months) was observed. The alteration of some biochemical characteristics of blood serum in transgenic pigs comparing to control animals was detected. The differences in correlation relationships between some biochemical characteristics of transgenic and control pigs were established.