51 consecutive patients with the clinical signs of aortic valve incompetence (AI) were evaluated by color-coded Doppler flow mapping (CDF) before angiography (AG). Quantitation of the severity of AI was performed by measurement of length and width of the extension of regurgitant jet (grade I-IV). After AG results both -AG and CDF- were compared. In 36 patients the results of both methods concurred exactly by use length in CDF. With CDF, the regurgitation was overestimated in 7 cases by one grade and underestimated in 8 patients also by one grade. Width of regurgitant jet relative to size of outflow space is a useful parameter to distinguish between mild and severe A1 (limit 0.50).CDF is a suitable method for semiquantitative assessment of AI. In presence of unequivocal CDF signs and in consideration of clinical and other patients findings AG will be dispensable before aortic valve replacement.