Assessment of depth of anesthesia is the basis in anesthesiologists work because the occurrence of awareness during general anesthesia is important due to stress, which is caused in the patient at that moment, and due to complications that may arise later. There are subjective and objective methods used to estimate the depth of anesthesia. The aim of this study was to assess the depth of anesthesia based on clinical parameters and on the basis bispectral index, and determine the part of bispectral monitoring in support to clinical assessment. Sixty patients divided into two groups were analyzed in a prospective study. In first group (group 1), the depth of anesthesia was assessed by PRST score, and in the second group (group 2) was assessed by bispectral monitoring with determination PRST score concurrently. In both groups PRST score was assessed in four periods, while bispectral monitoring is used continuously. For analysis were used the BIS index values from the equivalent periods as PRST scores. PRST score value 0-3, and BIS index 40-60 were considered as adequate depth of anesthesia. The results showed that in our study were not waking patients during the surgery. In the group where the depth of anesthesia assessed clinically, we had a few of respondents (13%) for whom at some point were present indicators of light anesthesia. Postoperative interview excluded the possibility of intraoperative awareness. In the second group of patients and objective and clinical assessment indicated at all times to adequate depth of anesthesia. The use of BIS monitoring with clinical assessment allows anesthesiologists precise decision-making in balancing and dosage of anesthetics and other drugs, as well as treatment in certain situations.