We examined the cases of 90 patients found to have univentricular heart at catheterization from January 1971 to January 1988. These patients are the 3.8% of the 2,322 children diagnosed of congenital heart disease by catheterization and angiography in this 17-year period of time. The mean follow-up was 9.5 years. The prognosis is poor: of the 90 patients, 50 died (55.5%) 43 of them in the first year of life. The actuarial survival rate is only the 38.5% at 5 years. Between the 56 children unoperated the mortality rate was the 62.5% and only the 16% (9 patients) survived with good functional results, class I and II of the New York Heart Association. The earlier palliative surgery changes the prognostic and the adverse natural history. The mortality rate in the operated group was the 44.1%. Another 44.1% (15 patients) of the operated group survived, 14 patients in class II and one in class III. The systemic-pulmonary artery shunts are the elective surgical procedure for important pulmonary stenosis, and the Fontan-type procedure is the elective for posterior, definitive repair.