This project aims to identify the possible causes of the turnover and estimate its future financial impacts on the personnel costs of an ethanol plant, more specifically of the Usina Santa Maria Ltda., located at BA 290, Km 43, Medeiros Neto – BA, in the southernmost region of Bahia, which has its office at Av. das Américas 700, block 3, room 306, Rio de Janeiro, RJ. A bibliography reference taken from books, scientific articles and websites, all of them related to subjects such as staff retention and turnover, was used for this main purpose. The data collection also involved a questionnaire to investigate the employees’ perception of the subject and a turnover model application to quantify with accuracy the costs of staff turnover and its impacts on the company.