The Purpose of this study is for clinical nurses to be aware of the significance of prevention against bacteriuria caused form foley catheterization, through probing variables related to the occurrence of bacteriuria which appears as the most frequent occurring infection, and try to lower bacteriuria by applying to nursing care at the clinical. For this study 46 patients with catheterization and the closed drainage system were sampled and investigated from among patients at Intensive Care Unit in Two hospitals affiliated to K University in Seoul. Those patients sampled had not shown bacteriuria before foley catheterization. The research design is to explore the effectiveness of prevention against bacteriuria in accordance with bladder irrigation and no bladder irrigation. Especially, the frequency of occurrence of bacteriuria examined so as to compare the effectiveness of bladder irrigation depending on the type of foley catheter between 2-lumen foley catheter and 3-lumen foley catheter. The results Were as follows. 1. The occurrence of bacteriuria in patient with bladder irrigation was 21.7%, while in patient without bladder irrigation 26.1%. 2. The occurrence of bacteriuria in patient without bladder irrigation according to duration of Indwelling catheter, was 4.3% after 48 h, 8.7％ after 72 h and 21.7% after 96 h. 3. In case of 2-lumen foley catheter the occurrence of bacteriuria in patient with bladder irrigation was 0% after 72 h, and 4.35% after 96 h. In case of 3-lumen foley catheter, the occurrence of bacteriuria in patient with bladder irrigation was 13% after 48 h, 8.7% after 72 h and 4.3% after 96 h. 4. The occurrence of bacteriuria according to duration of catheterization was 8.7% after 48 h, 8.7% after 72 h and 15.2% after 96 h. In sex, female was 35% and male 15.4%. 5. The occurrence of bacteriuria according to mental state was 15% in clear state, while 29.6% in mental disorder. 6. In regard to a kind of microorganism induced bacteriuria, Gram negative bacteria was 63.7%, Gram positve bacteria 36.3%.