Twenty eight cases of fetal hydrops are reported. A diverse aetiology was found. Fetal therapy was undertaken in 12 (42.9%). The overall survival rate was 36.8% (excluding elective terminations). However, when normal fetuses presenting from 20 weeks were considered, the survival rate was 64%. The results were combined with those of two other studies (making a total of 182 cases with fetal hydrops) to ascertain the value of pleural effusions in predicting outcome in such cases. In the 143 cases that did not end in a therapeutic termination of pregnancy, fetal pleural effusions predicted death (fetal or neonatal) with a sensitivity of 67%, a specificity of 53%, a positive predictive power of 68%, a negative predictive power of 52% and an overall accuracy of 62%.