The surgical management of patients with double-outlet right ventricle or transposition of the great arteries and straddling atrioventricular valves remains a subject of controversy. Biventricular repair has theoretic advantages because it establishes normal anatomy and physiology. In some instances, however, it seems to carry too high operative risk, and a univentricular heart repair is preferred. Since 1984, we have operated on 34 patients with double-outlet right ventricle (n = 15) or transposition of the great arteries (n = 19) with isolated straddling tricuspid valve (n = 17), isolated straddling mitral valve (n = 9), both mitral and tricuspid straddling (n = 2), or abnormal insertion of tricuspid (n = 7) or mitral (n = 2) chordae in the left ventricular outlet, precluding an adequate tunnel construction. Straddling was categorized according to the location of the papillary muscle insertion in the opposite ventricular chamber: type A, on the edge of the ventricular septal defect (n = 14); type B, on the opposite side of the ventricular septum away from the edge of the defect (n = 8); type C, on the free wall of the opposite ventricular chamber (n = 8). Abnormal chordal insertions were classified according to the location of their attachments around the edges of the defect. Three types of chordal distribution were identified: on the aortic conus, on the pulmonary conus crossing the ventricular septal defect, or around the defect closing it like a curtain. All but three patients had two ventricles of adequate size. Sixteen patients underwent palliation. Median age at the definitive operation was 6.5 months (range 1 to 130 months). Thirty patients underwent a biventricular repair and four had a univentricular repair. Biventricular repair was achieved by an arterial switch operation in 18 patients and by tunnel construction from the left ventricle to the aorta in 12. In isolated straddling of types A and B, the ventricular septal defect was closed by adjusting the septal patch on the ventricular side above the straddled papillary muscle. In type C, the patch was sewn over the papillary muscle by applying it on the septum. In double straddling, the ventricular septum was incised between the two papillary muscles, and an ellipsoid patch was used to reconstruct the septal defect, directing each subvalvular apparatus into its own ventricular chamber. When the abnormal chordae in the left outflow tract inserted on the aortic or pulmonary conus, the conus was incised and tailored to make a flap, leaving an unobstructed left ventricular outflow tract. In two patients the subvalvular apparatus was resected and reattached to the patch. Curtainlike chordae were a contraindication to biventricular repair in double-outlet right ventricle but not in transposition. There were four early deaths and one late death, all occurring in the group having biventricular repair. Death was due to myocardial ischemia (n = 1), right ventricular hypoplasia (n = 1), pulmonary hypertension (n = 1), and residual subaortic stenosis (n = 1). Two patients had moderate to severe postoperative atrioventricular valve incompetence, caused by a cleft in the mitral valve in one patient. Three patents were reoperated on for subaortic stenosis (n = 1), pulmonary stenosis (n = 1), and mitral regurgitation (n = 1). Mean follow-up of 30.7 ± 19.4 months was achieved in the survivors. All but one patient (univentricular repair) were in New York Heart Association class 1, without atrioventricular valve incompetence. Actuarial survival at 4 years was 85.3% ± 3%. We conclude that straddling or abnormal distribution of chordae tendineae of the atrioventricular valves does not preclude biventricular repair in double-outlet right ventricle or transposition of the great arteries provided that the ventricles are of adequate size. Curtainlike abnormal tricuspid chordae remain a contraindication to biventricular repair in double-outlet right ventricle.