Purpose This study aimed to investigate the olfactory functions of the acromegaly patients and to discuss the possible causes of olfactory dysfunction in acromegaly patients. Methods A case-control study was carried out in a tertiary referral center. 52 patients with acromegaly (Acromegaly group) and 52 healthy individuals (Control group) were included in the study. All acromegaly patients included in the study were in the late postoperative period. The Connecticut Chemosensory Clinical Research Center (CCCRC) test was carried out and olfactory bulb (OB) volumes were measured in both of the groups. Results There was a significant difference between the mean CCCRC total scores of the acromegaly and control groups (p = .000). The mean of right and left OB volumes in the acromegaly group was significantly higher than the control group (p = .004) Conclusion In this study, we found that acromegaly patients are likely to experience olfactory dysfunction. It is important to examine these patients' olfactory functions at the time of diagnosis and clinic follow-up.