Hospital acquired-pneumonia is the most frequently occurring hospital-acquired infection in intensive care units (ICU). The study group consisted of 233 patients treated over 12 months in the ICU of the 1st Department of General Surgery and Gastroenterological Surgery Clinics, University Hospital in Krakow. Patients were divided in two groups: experimental--consisting of 92 patients with hospital-acquired pneumonia, and control--consisting of 141 patients without the disease. The following risk factors of hospital-acquired pneumonia risk were analysed for both groups: length of stay in the ICU, duration of mechanical ventilation, kind of treatment applied, presence of a gastrointestinal tube, blood glucose levels. Significantly more patients with hospital-acquired pneumonia than controls had blood glucose level above 6 mmol/l (OR = 2.23). Monitoring and maintainment of glucose level within the normal ranges is an important element of successful treatment. In fact, glucose level is the only risk factor that can be easily modified compared with other analyzed factors.