Nijmegen breakage syndrome (NBS) is a rare autosomal recessive chromosomal breakage disorder characterized by microcephaly, growth delay, primary ovarian  insufficiency and predisposition to recurrent infections. Chromosomal instability is demonstrated by breaks and rearrangements. This condition was first described in 1979 in a mentally retarded Dutch boy. In 1981, it was found that his elder brother had the same clinical symptoms with severe immunodeficiency and the parents had close consanguinity. This led to the description of a new chromosome instability disorder which was named after the place in the Netherlands, where it was discovered. The case described here of two affected sistersis a retrospective report of an Indian family studied in 1976 in Mumbai, five years before this syndrome was named.