Real-time 3-dimensional echocardiography (RT3DE) offers the rapid acquisition of quantitative and qualitative anatomic data without the use of geometric assumptions. This study was designed to test the feasibility and potential superiority of RT3DE versus 2-dimensional echocardiography (2DE) and standard fluoroscopy for monitoring endomyocardial biopsies (EMBs). Thirty-eight consecutive EMBs performed under fluoroscopic guidance in 26 patients were monitored using 2DE and RT3DE alternately. Two reviewers scored each biopsy pass for visualization of the tip of the bioptome and location of the actual biopsy. Overall image quality was noted as good or poor, and the effect of image quality on tip localization was analyzed. A total of 243 biopsy attempts were made during 38 EMBs. The location of the biopsy was determined in 74% of the biopsies monitored with RT3DE, whereas 2DE demonstrated the location with certainty in only 43% of the biopsies (p <0.0001). On a procedure-by-procedure comparison, RT3DE was found to show the bioptome tip better in 23 of 38 biopsies, compared with 1 of 38 for 2DE (p = 0.001). In 14 of 38 EMBs, neither method was clearly better. In conclusion, RT3DE improves the ability to see the location of the bioptome during EMB compared with 2DE and fluoroscopy.