Relaxin was determined in healthy and pathological tissue samples from mammary gland, ovary, myometrium and cervix uteri of non-pregnant women. Relaxin could be detected in all groups of tissues examined. The highest values were found in healthy ovary, the lowest concentrations in the cervix, which is known as a target organ for relaxin activity during pregnancy. Mammary parenchyma showed the highest specific activity of all healthy tissues examined. The relaxin concentration in myoma tissue is significantly higher than in healthy myometrium.