The frequency and location of prominent left ventricular trabeculations were studied in 474 autopsy specimens from subjects evenly distributed by sex and age. These structures were observed in 323 (68%) of the hearts, and their frequency was similar in male (72%) and female (65%) subjects. Neither the frequency nor the location varied appreciably with age. Among the 323 hearts with prominent left ventricular trabeculations, 172 (53%) exhibited 2 or more; thus, the total number of trabeculations was 582. Of these 582 trabeculations, 493 (85%) were septoparietal bundles that inserted into both the free wall and the septum. Trabeculations also were observed between two points on the ventricular septum in 37 (6%) of the hearts and between two points along the free wall in 36 (6%). Less common patterns included trabeculations between the ventricular septum and the posteromedial papillary muscle in 10 hearts (2%), the ventricular septum and the anterolateral papillary muscle in 2, the free wall and the posteromedial papillary muscle in 2, the two papillary muscles in 1 and the apex and the ventricular septum in 1. Accordingly, prominent left ventricular trabeculations are considered to be common variants of the normal human heart. Their size, shape and location may lead to their being misinterpreted, possibly as mural thrombi, by two-dimensional echocardiography.