The terminal and other chorionic villi and fibrinoid of the mature human placenta were morphologically and quantitatively examined in pregnant women of different ages. The aim of this research was to compare the results and to confirm if there is some difference in the structure of placenta related to the age of pregnant women. We examined 30 human placentas, regular pregnancies and delivery. The examined group of women were of age between 20 and 45 years, and they were divided into two groups: 1) pregnant women 20-35 years old; 2) pregnant women over 35 years old. Relative and absolute variables were stereologically examined and compared as follows: the surface density and absolute surface of terminal and other villi and fibrinoid. No significant differences in surface density of terminal villi and fibrinoids in older or younger pregnant women's placentas. Surface densities of the other placentas villi in younger pregnant women compared to older are significantly increased. Absolute surface of terminal villi and fibrinoid in these two examined groups of pregnant women are not significantly different. Absolute surface of the other placenta villi in younger pregnant women compared to older pregnant women is significantly increased.