Infections that occur within the surgical intensive care unit represent a significant cause of patient morbidity and mortality. In addition, hospital-related infections prolong hospital stay and increase hospital-charges. Moreover for the patient with tracheostomy, the possibility of cross-infection may impose an added risk when the general condition is poor. This study was undertaken to investigate the incidence of upper respiratory infection in patients with tracheostomies who had respiratory care in the surgical intensive care unit. The total number of cases in this study was 20, and the specimens for bacteriologic culture were taken especially from the regions of the upper respiratory tract via tracheostomy tubes on the 1,3,5,7 and 10th day after tracheostomy. The results obtained from the bacteriologic culture were as follows: 1_ The most frequently found organism was Pscudomonas aeruginosa, and newxt was staphylococcus, followed by beta-hemolytic streptococcus and Escherichia coli. Gram negative bacilli were 58.9% of all cultured organisms. 2) The greatest number of organism was seen on the third day and frequency of mixed growth was increased in process of time. 3) The comparative sensitivity test of Pseudomonas seruginosa showed that all strains were resistant to ampicillin, erythromyclin, penicillin and tetracycline and 70% of strains were sensitive to amikacin.