Laser ablation of thrombus has potential clinical relevance in the treatment of ischemic stroke. Timely removal of artery occluding thrombus can prevent irreversible damage of cerebral tissue due to anoxia. This study measures ablation of a thrombus phantom using a frequency doubled Nd-YAG laser at 532 nm . This unique laser was designed to produce long pulses in the 50-150 μs range for ablation of soft materials. Comparisons are made of the ablated mass after irradiation by 25, 50, and 100 mJ delivered through a 300 μm quartz optical fiber. Spectrophotometric techniques were used to measure ablated mass and ablation efficiencies were calculated. These results are compared with previously published ablation studies using 1 μs laser pulses. Bubble dynamics are demonstrated by stop action photography using a CCD camera.