The objectives of this study were to determine whether three-dimensional ultrasonography can provide more cardiac views than two-dimensional ultrasonography and to develop a standard technique. Eighteen women, 16 to 26 weeks' gestation, were scanned with two-dimensional ultrasonography for 10 minutes or less to obtain fetal heart views. Three-dimensional ultrasonography was used (< or =10 minutes) to obtain up to 4 acquisitions of the fetal heart: 4-chamber view, left parasagittal, transverse, and longitudinal nonstandard. Views were later extracted from saved volume data, comparing the yields of two- and three-dimensional ultrasonography. The 4-chamber view was obtained in 15 (93%) of 16 cases on both two- and three-dimensional ultrasonography. On two-dimensional ultrasonography, the left outflow tract was obtained in 68% of the cases; on three-dimensional ultrasonography, the left outflow tract was obtained in 46% from the 4-chamber view acquisition and in 100% from the left parasagittal acquisition. On two-dimensional ultrasonography, the right outflow tract was obtained in 68% of the cases; on three-dimensional ultrasonography, the right outflow tract was obtained in 86% from the 4-chamber view acquisition and in 71% from the left parasagittal acquisition. Aortic and ductal arches were obtained in 12% and 18%, respectively, on two-dimensional ultrasonography. On three-dimensional ultrasonography the aortic and ductal arches were obtained in 66% and 86%, respectively, from the 4-chamber view acquisition and in 57% and 71%, respectively, from the left parasagittal acquisition. Three-dimensional ultrasonography permitted a greater number of cardiac views to be extracted from volume data than did two-dimensional ultrasonography.