Background: Nosocomial infections (NIs) have increasingly resulted in death and patients have to bear high treatment costs. Healthcare personnel could play a prominent role in prevention and control of NIs.Objectives: The aim of this study was to evaluate NIs in patients admitted to a teaching hospital in Ahvaz, southwest of Iran, during 2013.Patients and Methods: The present study was a cross-sectional study conducted in Razi Hospital, Ahvaz during 12 months from March 2013 to March 2014. All patients hospitalized with no signs and symptoms of infection within 48 hours of admission and presenting signs and symptoms of infection after 48 hours of hospitalization were included in the study. Data about patients’ age, sex, site of infection, ward of hospitalization and type of NIs were collected. Bacterial strains were isolated from various clinical samples of patients and identified by conventional methods.Results: The incidence of NIs was low (i.e.<2%). Among 16936 admitted patients in this hospital, 174 patients (79 males and 95 females) with a mean age of 51.7±24.6 years (range, 5 to 90 years) were diagnosed with an NI. Incidence density of NIs were 3.18% in infectious diseases ward, 2.17% in intensive care unit (ICU), 2% in orthopedic ward, 0.68% in obstetrics and gynecology (OBGYN) ward and 0.278% in general surgery. Regarding the etiology of infection, coagulase-negative staphylococci in 23.69%, Bacillus in 21.05%, Escherichia coli was found in 18.42%, and coagulase-positive staphylococci in 13.16% of the cases. The results indicated that coagulase-negative staphylococci was the most frequent pathogen.Conclusions: The frequency of NIs in this hospital was lower in comparison with other worldwide studies. However, low incidence of health care-associated infections in our study may be due to under diagnosis and underreporting of such infections by health care staff.