Background: Anxiety is an emotional situation marked by apprehension, agitation, tachypnea, tachycardia and hypertension. There has been a recent rise in the amount of patients who have undergone surgery for morbid obesity. The STAI anxiety scale was the primary tool for measuring anxiety levels. Aim: The purpose of this research was to evaluate the levels of anxiety in patients with morbid obesity both before and after surgery and to identify the factors that contribute to this anxiety. Methods: This is a prospective cohort study that uses quantitive descriptive methodology. The study included 129 patients planned for laparoscopic sleeve gastrectomy. The STAI anxiety scale was used to assess anxiety levels both before and after surgery. The patients' pain levels were assessed using VAS during the postoperative period. Results: In comparison of genders, female patients' pre-op anxiety levels were statistically significantly higher (p= 0.001). The anxiety levels differed significantly between preoperative and postoperative patients. Even it has not reached a significant level, the elderly group had lower pre-op anxiety scores than the others, but higher post-op anxiety scores. Educational level didn’t effect anxiety scores. The correlation between patients' anxiety levels and VAS pain levels was found to be statistically significant (p=0.001). Conclusions: Anxiety plays a significant role in influencing postoperative pain and the subsequent analgesic needs after sleeve gastrectomy procedures. Postoperative pain is the primary cause of perioperative anxiety. Females exhibit higher preoperative anxiety levels than males.