The interaction of pulsed Nd:YAG laser radiation and atherosclerotic vessel wall is reported. The effects in the area of radiation were examined at an infrared, green, and ultraviolet wavelength at variable pulsewidths. The laser beam was focused directly on the plane surface of the tissue. The macroscopic and histologic examinations demonstrate that thermal damage of tissue is higher at an infrared wavelength than at a green wavelength and respectively at an ultraviolet wavelength. With increasing pulsewidth an increase of coagulation and necrosis of plaque material and adjacent vessel wall can be noted. The results show that for the precise ablation of plaque without adjacent vessel wall injury short pulsed ultraviolet radiation is preferable.