A scar is the fibrous mass that results from healing of tissue which is destroyed by injury or disease. Scars can be secondary to surgery, burns, trauma, chronic wounds, disease conditions like acne, chicken pox scar, etc and also includes striae. This chapter will not only address the use of lasers and light sources for acne scars, other atrophic scars, hypertrophic and miscellaneous scars but also discuss the strategies to minimize the scar formation. Lasers for scar prevention are becoming increasingly popular. The treatment must target both the mechanism of abnormal scar formation and scar morphology itself. Acne scars are polymorphous and require a multimodal approach for successful outcome. Icepick scars, boxcar scars and rolling scars are 3 basic types of scars. Hypertrophic scar is linear, red, raised firm scar, confined to the original injury site; sometimes pruritic, occurs on sites under constant pressure and stretching and usually arise within 1 month of injury. Stretch marks are benign, but can have great psychological implications especially in female. They results due to changes in extracellular matrix, elastin and collagen. The fractional CO2 and erbium Yag laser significantly improves the mature stretch marks, by stimulating new collagen and elastin synthesis.