During the last 10 years, 17 children with transposition of the great arteries (TGA) were admitted to the Cardiology Institute of Abidjan: 1 case between March 1978 and December 1985, 16 cases between January 1986 and December 1989. The average age was 58 days (range 5 to 270 days) at the first consultation, and 90 days (5 to 270 days) at the time of admission. The diagnosis was confirmed by echocardiography and hemodynamic investigation in 12 cases. There were 9 simple forms of TGA, 7 with ventricular septal defects (VSD) and 1 with VSD and pulmonary stenosis. Two children were taken back by their parents before any treatment was given. A Rashkind atrial septostomy was carried out in 11 children which increased aortic oxygen saturation from 35 +/- 18 percent to 57 +/- 19 percent; there were 3 unsuccessful procedures in children aged 2, 3 and 5 months with 2 deaths. Five patients later underwent surgical correction by a Senning procedure in 4 cases and anatomical correction in 1 case with VSD. All are well after an average 15 months follow-up (1 to 48 months). One of the 8 children awaiting surgery died. Therefore, TGA is not a rare abnormality in Black Africa; it represents 2 percent of the 887 cases of congenital heart disease observed during the same period. The inadequacy of means of diagnosis is certainly the cause of the relatively low incidence of this malformation, of the considerable delay in under specialist care and, as a consequence, of the greater difficulties in treatment, especially with regards to atrial septostomy.(ABSTRACT TRUNCATED AT 250 WORDS)