Recurrent pregnancy loss affects 1% of patients, an incidence higher than expected from the prevalence of spontaneous abortion in the general population. Some couples may show a tendency for aneuploid conceptions. Genetic counseling and amniocentesis or chorionic villus sampling were offered to 305 couples with a history of two or more pregnancy losses and normal parental karyotypes, with no additional known risk factors for aneuploidy. Prenatal diagnostic procedures were performed in 96 pregnancies. Two hundred nine couples declined active intervention, and these pregnancies were followed to delivery. Five chromosomal abnormalities (1.6%) were diagnosed in the study group. A group of 979 prenatal diagnostic procedures performed in "low-risk" pregnancies in Hutzel Hospital was used as controls, and three chromosomal anomalies (0.3%) were diagnosed. That the rate of aneuploid conceptions was statistically significantly (P = .02) higher in low-risk couples experiencing recurrent pregnancy loss than in controls points to a tendency for chromosomal aberrations in their offspring and suggests a place for prenatal diagnosis in subsequent pregnancies.