Monosomy 9p syndrome, also known as Alfi syndrome, has been described as a contiguous syndrome characterized by mental retardation, developmental delay, and facial dysmorphisms. Males with monosomy 9p often express variable degrees of feminization, although the genitalia of females will be normal. In the present report, we describe a case of ambiguous genitalia and intra-abdominal testicular development, with a derivative chromosome 9 arising from a translocation between 9p23 and Yq heterochromatin. Pathologic examination of the testes showed germ cell hypoplasia of the seminiferous tubules. fluorescence in situ hybridization, spectral karyotyping, and array comparative genomic hybridization were used to characterize the genetic changes.