Introduction: Prolonged intubation is the main indication for tracheostomy in intensive care units (ICUs). The aim of this study is to detect the factors affecting decannulation of tracheostomy done for patients in ICUs. Patients and Methods: It is a prospective cohort study. It was conducted in trauma ICUs of a tertiary care center. It included all patients who were admitted to ICUs during the period of the study and were subjected to prolonged intubation, mechanical ventilation and tracheostomy during their admission in ICUs, regardless of their age and sex. Decannulation was considered when no longer need for tracheostomy and after fulfilling criteria of decannulation. Decannulation was one staged and was considered successful if there was no need for reapplication of tracheostomy during six months of follow up. The participants were divided into two groups; successful decannulation group (DG) and failure of decannulation group (FDG). Factors affecting decannulation were detected by comparing the two groups; (DG) and (FDG). Results: DG included 52 patients and FDG included 29 patients.  Tracheal stenosis and low conscious level were the cause of failure of decannulation in 44.8% and 41.4% of patients respectively. Statistically significant shorter duration of intubation and duration of mechanical ventilation were found in DG with p. value 0.015 and 0.025 respectively. The mean cannulation time of DG group was 49 days. Conclusion: Duration of intubation, duration of mechanical ventilation, development of tracheal stenosis, low conscious level and bad chest condition are the factors ruling decannulation of tracheostomy.