Preoperative anxiety can negatively impact patient outcomes by influencing the intraoperative requirements for anesthetics and analgesics, increasing postoperative pain intensity, and augmenting the need for analgesia. Moreover, it may contribute to higher rates of postoperative morbidity and mortality following certain types of surgery. This study investigates the anxiolytic and sedative properties of sublingual melatonin as a premedication agent in young females undergoing cesarean section under spinal anesthesia. A double-blind, randomized, placebo-controlled trial was conducted in Nasiriyah, Iraq. Eighty females were included, 40 in each group, based on specific inclusion and exclusion criteria. Premedication was administered in the morning, 60 minutes before the procedure. In the melatonin group (M), patients received 10 mg of sublingual melatonin, while the placebo group (P) received placebo premedication. Anxiety and sedation levels were evaluated three times: before taking premedication, five minutes before the insertion of the spinal needle, and one hour postoperatively, using the visual analog scale and Richmond Sedation Scale. The results show a highly significant P-value regarding anxiety levels between the M Group and P Group (p-value < 0.001). There was a significant difference in the median sedation scores between the studied groups at pre-spinal insertion and postoperatively (p-value < 0.001). The mean heart rate in the M Group was significantly lower than in the P Group (p-value = 0.0019). Significant differences were noted in systolic and diastolic blood pressures between the two groups, measured five minutes before and after spinal needle insertion (p-value < 0.001). These findings contribute to understanding the impact of sublingual melatonin as an anxiolytic and sedative premedication agent on patients undergoing elective cesarean sections under spinal anesthesia. Further research is warranted to fully elucidate the benefits and implications of melatonin administration in such procedures.