Epithelial ingrowth (EI) is a rare complication of any type of excimer laser surgery with a flap, but still is the most frequent (around 1%) and the most dangerous of all. Although etiology is unclear, there are several risk factors the surgeon must consider when deciding between surface ablation or flap surgery: dry eye, diabetes, or previous Radial Keratotomy (RK). If Laser-assisted in situ Keratomileusis (LASIK) is decided, problems with the flap are also a big factor as well as relifting. The presence of EI has been proved to increase when the flap is lifted again. The main problem of epithelial ingrowth is the lack of symptoms when is still small. They are: bad vision, foreign body sensation, red eye, glare, or haloes. However, when patient complaints, EI may be advanced and if left untreated may become a sight-threatening complication. Therefore, the clue in the diagnosis and management of this complication is early diagnosis, only made by careful slit lamp evaluation. Once epithelial ingrowth is diagnosed, two roads must be followed: (1) Careful observation when the cells are small, less than 2 mms, and have a demarcation line. (2) Treatment when cells are not limited and progression is observed. Lifting and cleaning must be the last step and the first line of treatment must be Yttrium aluminum Garnet Laser (YAG) laser of the cells as was first proposed by Alio et al. Since treatment is difficult, prevention is key in avoiding EI. Careful flap manipulation, use of bandage contacts, stitches, or glue are important when borders of the flap are compromised. However, a very important way to prevent epithelial cells from growing under the flap is avoiding creating one and instead changing surgery to superficial excimer laser ablation.