Optimal management of dextrotransposition of the great arteries with intact ventricular septum is currently an arterial switch procedure performed in the first 2 weeks of life. However, a subgroup of patients presents for surgery beyond this time for reasons of sickness, size, or late referral. Experience with 11 such patients (mean age at first-stage procedure, 4.5 months) has revealed that the left ventricle can be prepared by a surprisingly short interval period (median, 9 days) between a first-stage preparatory operation (pulmonary artery band with or without a shunt) and a subsequent second-stage arterial switch procedure. Serial two-dimensional echocardiography showed that left ventricular mass increased by a mean of 85% during this short interval. Mean left ventricular-right ventricular-pressure ratio as measured by cardiac catheterization increased from 0.5 +/- 0.08 a median of 7 days before the first stage to 1.04 +/- 0.29 a median of 7 days after the first stage. One patient underwent a Senning procedure because of an intramural left coronary artery. The other 10 patients underwent an arterial switch, with no early deaths. Median hospitalization after the arterial switch was 8 days. There has been one late death at 5 months. No patient has been detected to have abnormal ventricular function, although trivial to mild aortic regurgitation has been commonly observed with color flow mapping. These results have encouraged us to offer a two-stage arterial switch procedure to appropriate infants with an interval period of approximately 1 week. Both stages can be performed at one hospitalization, with important psychosocial, logistic, and financial advantages.