In an effort to help develop an understand new laser sources for clinical laser angioplasty, quantitative evaluations were performed to see if tissue ablation efficiency was dependent upon human plaque composition. Previous reflectance and transmission spectroscopy on variable composition necropsy aorta showed higher absorption at 460-500nm by yellow atheroma. Therefore, two laser sources - a pulsed dye laser (480nm) and a continuous Argon laser (488nm) were used to ablate variable composition necropsy atherosclerotic specimens. For both laser sources, the ablation efficiency increased 5-10 fold for yellow atheroma relative to both white atheroma and normal aorta. Thus, we have demonstrated selective plaque ablation of yellow pigmented atherosclerotic material using laser sources of a specific wavelength (either pulsed or low-power continuous) which correspond to higher tissue absorption characteristics. These data may be important in permitting safe and more efficient atheroma ablation in specific clinical situations during experimental laser angioplasty investigations.