Familial hemophagocytic lymphohistiocytosis (FHLH) is a genetic heterogeneous autosomal recessive disorder. We report two siblings with FHLH caused by a PRF1 mutation. The first child died in utero with hydrops fetalis and the second presented soon after birth with fatal multiple organ failure. Post-mortem DNA analysis showed a homozygous c.666C>A (p.His222Gln) mutation in the PRF1 gene in both cases, with their non-consanguineous parents being heterozygous for the same mutation. Review of the literature shows that perinatal presentation of FHLH is rare. Diagnosis is difficult because in most cases histologic examination reveals no hemophagocytosis and the disease is rapidly fatal. The association between hydrops fetalis and FHLH has been reported in four previous reports. We present the first case of hydrops fetalis caused by FHLH, confirmed by DNA analysis. FHLH should be included in the differential diagnosis of non-immune hydrops fetalis and neonatal multiple organ failure.