The results of composite epidemiological, virological and morphological studies of intrauterine rubella infection performed in 1979, in the period of maximum increase of rubella incidence in Moscow for 11 years (1969-1979) are presented. Investigations of 125 foci of rubella established a relatively high frequency of contacts of pregnant women with the source of infection in families of rubella patients. Twenty-nine cases of clinically manifest and inapparent rubella among pregnant women were detected and confirmed in the laboratory; intrauterine infection at 3-17 weeks was established in 16 out of 18 virologically examined women. The ratio of the disease forms was 3.5 : 1. Using laboratory methods of investigations, rubella of pregnant women was confirmed in 100% cases. From the aborted and fetal materials collected in the disease or inapparent infections of pregnant women rubella virus was isolated in 88.9%, marked pathomorphological lesions were found in organs of 61% of the fetuses examined. The organotropism of rubella virus was confirmed by a high rate (87%) of virus isolation from placenta and umbilical cords as well as by localization of morphological lesions in these organs and in the eye lens tissues. These characteristics of marked teratogenic potentials of the circulating virus strains indicate the necessity of organization of regular epidemiological surveys of rubella in pregnant women for prevention of congenital rubella in the USSR.