The finding of homozygosity for a pericentric inversion of chromosome 9 is rare.  We describe one related case of homozygosity for inv(9) identified in amniocytes. In this case, parents were heterozygotes for the inv(9); 46,XX,inv(9)(p11q13) and 46,XY,inv(9) (p11q13). The incidence of inv (9) is highest in the Black population (3.57%); slightly above average in Hispanics (2.42%); and relatively low in Whites (0.73%) and Asians (0.26%). Proband resulted in a normal term infant who at age 2 months was phenotypically and developmentally normal. Homozygosity for inv(9) is a normal chromosome variant with a frequency of 1 to 3% in the general population. Presumably, inv(9) homozygosity results from the high frequency of inv(9) heterozygosity, and is a normal variant. In addition, more reports of inv(9) homozygosity detected prenatally are needed to assess its frequency and outcome.