A two year prospective analysis of all second trimester fetuses (16-22 weeks of gestation) with hyperechogenic bowel was undertaken. Hyperechogenic fetal bowel (sonographic echogenicity similar to or greater than that of surrounding fetal bone) was diagnosed using strict criteria. Outcome of affected fetuses was ascertained from hospital records, health care workers and autopsy reports, up to six months of age. Sixty consecutive fetuses were identified, of which 48 (80%) were liveborn. Six pregnancies were terminated, four ended with an intrauterine fetal death and two died at birth. The incidence of cystic fibrosis and aneuploidy were each 5%, and there were no cases of congenital infection. Intrauterine growth retardation was recorded in six fetuses (10%), four of whom died perinatally. Eighty-two percent of fetuses (28/34) with isolated hyperechogenic bowel had a normal outcome.