A port-wine stain (PWS) is a congenital capillary malformation that is seen in 0.3-0.5% of newborns. Although many types of lasers have been used to treat PWSs, few studies have investigated the efficacy of 577-nm Pro-Yellow lasers. The aim of this study was to establish the efficacy of Pro-Yellow lasers in PWS treatment. In total, 26 patients, comprising 15 females (57.7%) and 11 males (42.3%) with a mean age of 24.7 +/- 11.8 (range 1-50) years were included in the study. All were treated with a 577-nm Pro-Yellow laser at 4-week intervals, 3-10 times. The sessions initially used scan mode and a fluence dose of 24 J/cm(2) per session, on average. The mean dose was increased by 4 J/cm each session and the maximum dose administered was 44 J/cm2. A mean regression of 68.8 +/- 13.9% in the size of the lesions over 5.23 +/- 2.7 sessions was observed. There was no statistically significant difference between the female and male patients when they were compared in terms of the number of treatment sessions (p = .789) and treatment success (p = .39). These case series demonstrate that the Pro-Yellow laser is a safe and well-tolerated treatment for PWSs. However, deep-seated lesions required more treatment sessions and it was observed that clinically the lesions did not completely disappear.