One of the most common orthopedic problems in the authors’ practice is flatfoot and, although it is most commonly treated conservatively, there is still lack of consensus about the type of surgical treatment that is best recommended in a specific patient. Keeping in mind that medial soft tissue reconstruction alone has not proved enough as an isolated procedure and that osteotomies and arthrodesis are considered more invasive surgery, arthroereisis is a quick, easy, and reproducible technique that seems to have good results without major complications in the correct patient. Indications, biomechanical principles, and technique are described in this article.