The primary aim of this study was to establish the incidence and characteristics of postoperative cognitive dysfunction (POCD) in patients undergoing noncardiac surgery. In addition, the aim was to determine whether age and comorbidities have an infl uence on the incidence of POCD. Patients and Methods: Sixty-three patients treated in Rijeka University Hospital Centre completed this prospective study. The following parameters were determined in each patient: age, gender, level of education, chronic illness (hypertension, diabetes and neurologic diseases), type and length of anesthesia, and length and severity of surgical procedure. All patients had normal neurologic and mental state preoperatively. The Montreal Cognitive Assessment (MoCA) test was used to determine cognitive function before surgery, then 7 days and 3 months after surgery. Patients younger than 18 and older than 75 were excluded from the study, as were those suffering from intellectual disability and dementia. Results: Twenty-fi ve (40%) patients had signs of cognitive dysfunction 7 days after surgery, which persisted in 8 (13%) patients 3 months after surgery. There was a significant difference (p<0.0001) in patient MoCA scores before surgery and 7 days after surgery. A signifi cant difference (p<0.0001) was also found between patient MoCA scores 7 days and 3 months after surgery, whereas there was no difference (p=0.06) between the scores recorded before surgery and 3 months after surgery. There was no statistically signifi cant difference after dividing patients into groups according to age and comorbidities. When analyzing MoCA test by subcategories, statistically signifi cant differences between the mentioned time periods were found in the following subcategories: executive functioning (p= 0.0008), attention (p=0.019), language and fl uency (p<0.0001), and delayed remembering (p=0.017). The overall incidence of POCD in our study was 40% seven days after surgery and 13% three months after surgery, which was similar to those reported in the literature. The incidence of POCD can vary greatly between studies, as there are no clear and standardized criteria for diagnosis of POCD. Patient MoCA scores decreased 7 days after surgery compared to those recorded before surgery, although they recovered in most patients 3 months after surgery. These results are comparable with literature data from studies that used the same cognitive test. Controlled longitudinal studies report similar fi ndings, indicating the transient nature of POCD in most patients after several years. Executive functioning, attention, fl uency and delayed remembering were most affected in our study patients, whereas naming, abstract thought and orientation were not affected either before or after surgery. Of all categories, executive functioning can have most serious effect on the patient quality of life and postoperative risk. Several studies that investigated which cognitive functions were most affected report results similar to ours. Interestingly, patients with mild cognitive impairment and dementia had signifi cant differences in abstract thought and orientation, which implicates a different pathophysiological process than the one involved in the development of POCD. A limitation of our study was a small number of patients, which limited interpretation of the results. Furthermore, motor skills should also be evaluated thoroughly in future studies, as MoCA test is quite superficial in this regard. Lastly, a healthy control should be included for assessing the outcome and length of POCD. In conclusion, surgery led to the development of POCD in a significant number of patients, although most of them recovered in 3 months. POCD is a disease that deserves further study as it can have a signifi cant impact on the quality of life and functioning in the postoperative period.