A procedure is proposed for the noninvasive determination of fetal rhesus factor in rhesus-negative pregnant women, which is based on the detection of the RHD gene in peripheral maternal blood by a PCR technique. The studies have shown the high sensitivity and specificity of determination of rhesus factor in a fetus at more than 15 weeks gestation. The technique does not require the use of such invasive and pregnancy-threatening procedures, as amniocentesis, cordocentesis or chorion biopsy. Furthermore, determination of fetal blood rhesus factor in rhesus-negative patients makes it possible to reduce expenses on the management of pregnancy, to avoid multiple determination of antibody rhesus and prevention of rhesus immunization, and to timely initiate therapeutic and preventive measures.