The pulse width of the previous model of pulsed dye laser was fixed at 0.45 millisecond, whereas the pulse widths of the latest model of PDL are tunable ranging between 0.45-40 milliseconds. The long-pulsed PDL has been proven to be safe and more effective in treating certain vascular abnormalities including adult port-wine-stain and small leg vein.9-12 In the present study, we would like to investigate the effect of pulse widths on the treatment response of keloidal and hypertrophic sternotomy scars to the 595-nm PDL.