In this prospective study, 93 intensive care unit (ICU)-acquired infections seen in 131 ICU patients were evaluated. Infection rates were found to be 70.9 in 100 patients and 56.2 in 1,000 patient-days. Pneumonia (35.4%) and bloodstream infections (18.2%) were the most common infections; Staphylococcus aureus (30.9%) and Acinetobacter spp. (26.8%) were the most frequently isolated microorganisms. The results of multivariate logistic regression analyses estimating the risk factors for ICU-acquired infections were as follows: length of stay in ICU (>7 days) (odds ratio [OR]: 7.02; 95% confidence interval [CI]: 2.80-17.56), respiratory failure as a primary cause of admission (OR: 3.7; 95% CI: 1.41-9.70), sedative medication (OR: 3.34; 95% CI: 1.27-8.79) and operation (before or after admission to ICU) (OR: 2.56; 95% CI: 1.06-6.18). In logistic regression analyses, age (>60 years) (OR: 3.65; 95% CI: 1.48-9.0), APACHE II score >15 (OR: 4.67; 95% CI: 1.9211.31), intubation (OR: 3.60; 95% CI: 1.05-12.39) and central venous catheterization (OR: 7.85; 95% CI: 1.6138.32) were found to be significant risk factors for mortality. The difference in mortality rates between patients with ICU-acquired infection and uninfected patients was not statistically significant (mortality rates: 42.3 and 45.6%, respectively). A high incidence of nosocomial infections was found, and the risk factors for ICU-acquired infections and mortality were determined.