Background: TOF monitoring or muscle nerve monitoring is a technique which is used after anaesthesia has ended to examine the performance of the patient's muscles following the use of muscle blocking drugs during anaesthesia. Stimulating the nerves in the patient's, TOF provides an accurate assessment of the need for a relaxant during the operation. The purpose of the present study was to investigate the rate of muscle relaxation using the TOF (train of four) technique in patients undergoing surgery in Shariati Hospital at the time of admission and discharge time. Materials and Methods: The study tools was a checklist prepared by a research team that contained demographic information, type of surgery, duration of operation, BMI, and information displayed by the nerve stimulator. The rate of TOF at admission and at the time of discharge was measured for all the patients. Subsequently, the patients were divided ito two groups based on the fixity and alterability of the TOF rate. Results: 400 patients were studied in this study. The TOF rates of the two groups of patients at admission and the time of discharge were 81/4 and 89/9 respectively. The highest alteration of TOF rate (57%) belonged to men. Moreover, the maximum level of TOF variation in the recovery phase was observed after the spine surgey were %87/5 and the minimum level belonged to abdominal surgey (%17/5). The duration of the operation for the groups with and without TOF variations was 125 and 75 minutes respectively. The subjects in the groups with and without TOF variations were 44 anf 34 years old respectively. Finally, the BMI level in the groups with and without TOF variations were 27 kg/m2 and 28 kg/m2 respectively. Conclusion: Neuromuscular relaxation variation is likely to be affected by several determinanats. Moreover, TOF monitoring reduces the likelihood of the continuation of neuromuscular block in PACU and post-discharge time. Hence, it reduces the likelihood of the occurrence of respiratory complication and aspiration.