Introduction- Ideal timing for tracheostomy in intensive care units (ICUs) is stil a controversial issue forcritically ill patients undergoing prolonged mechanical ventilation (MV). Objectives- The objective of the present study is to determine proper timing of the tracheostomy and its impact onmultiple clinical outcomes of the adult patients in ICUs undergoing prolonged MV. Methods and Materials- The present study consisted of a sample of 65 ICU adult patients who weresubmitted to open surgical tracheostomy and divided into two groups: 30 patients inthe early tracheostomy (ET) group (within 1–10 days post intubation), and 35 patients