A new case of ring chromosome 2 is described and compared with the five cases hitherto reported. The clinical picture includes a severe pre- and postnatal growth failure, microcephaly, psychomotor retardation, and some minor dysmorphic features. Cytogenetic studies revealed a ring 2 structure and aneuploidy. Banding analysis failed to demonstrate a substantial loss of chromosomal material. Enzymologic studies revealed a decrease of red cell acid phosphatase activity suggesting the localization of its gene inthe 2p25 leads to 2 pter region.