A survey was sent to the American members of the National Urea Cycle Disorders Foundation to ascertain the types and extent of stress imposed on families who have a child with a urea cycle defect. Forty percent of the surveys were returned. The greatest sources of stress were financial, fear of death, and the restrictions imposed by the diet. Other than removal of the economic stress and uncertainty, the results did not suggest that any specific support systems required augmentation. Instructions to mitigate frustrations occurring in emergency situations would, however, be a great help to families.