The concept of selective photothermolysis with the 577-/585-nm pulsed dye laser (PDL) revolutionized treatment of relatively common port wine stain (PWS) birthmarks. The majority of PWS can be significantly lightened with the PDL. However, few PWS are lightened completely with PDL and up to 20% hardly lighten at all. PDL-resistant PWS exist in any large cutaneous laser practice and constitute a difficult management problem. This article discusses the proposed cause, and currently available and emerging options for PDL-resistant PWS. These include higher power, longer wavelength, variable pulse width lasers with selective epidermal cooling such as 595-nm PDL, 755-nm alexandrite, 810-nm diode, 1064-nm neodymium:yttrium-aluminum-garnet, and intense pulse light systems. Other promising modalities include topical and systemic photodynamic therapy, electrical optical synergy technology, pulse stacking of similar or differing wavelengths, use of optical clearing agents in conjunction with laser, and erbium laser epidermal stripping before laser treatment.