The aim of this study was to evaluate the incidence of valve lesions after radiofrequency catheter ablation of accessory atrioventricular pathways using the retrograde transaortic approach. Patients who presented no preexisting detectable valve lesion prior to catheter ablation and who underwent a comparable echocardiographic examination prior to and after catheter ablation were included for data analysis. From January 1991 until May 1993, 113 patients underwent radiofrequency catheter ablation of a left-sided accessory atrioventricular pathways at our institution. Fifty-nine patients were included in this study. Five patients (8.4%) developed new valve lesions after radiofrequency catheter ablation. There were two cases (3.3%) of aortic regurgitation and four cases (6.7%) of mitral regurgitation. In the majority of cases only mild valve regurgitation was detected. A hemodynamically significant valve lesion was observed in a single patient (1.6%). We speculate that the new onset of valve lesions is mostly due to catheter manipulations rather than due to tissue injury related to radiofrequency current application. Echocardiographic examinations prior to and after radiofrequency catheter ablation of accessory pathways may contribute to a further reduction in intervention-related complications.