Background The patient discharge process is one of the most important factors affecting patient satisfaction, which can affect the quality of services of hospitals, and its prolongation can be detrimental in bed management and result in admission delays for new patients. This study aimed to investigate the factors contributing to the prolongation of the discharge process in Tehran's pediatric teaching hospital. Methods The present study was a descriptive cross-sectional study carried out on 300 patients discharged from one of the pediatric teaching hospitals in Tehran in 2019. This study was conducted using a mixed-method and composed of two parts: quantitative and qualitative. Initially, in the quantitative stage, the statistical form was used, the average discharge time in different wards of the hospital was measured using the stopwatch method, and the data were analyzed using SPSS V. 25 software and descriptive statistics. Subsequently, to identify the causes of the prolonged process in some departments and identify practical solutions, a qualitative approach was used, including observations, file reviews, Focus Group Discussion (FGD), brainstorming with experts from the Quality Improvement Office, ward secretaries, clearance unit experts, pharmacy experts, and ward supervisors. Finally, the factors were prioritized and approved using the nominal group method. Results The average discharge time was 3 hours and 7 minutes; the shortest discharge time belonged to the blood ward, and the longest discharge time belonged to the kidney ward. The causes of delay in discharge were divided into two categories: organizational and human factors. The most crucial elements were the time required to issue discharge orders, write patient summaries, and maintain patient files. Conclusion For improving the quality of the discharge process and patient satisfaction, solutions such as having assistants write file summaries before the morning round, sending files out of the ward on time, hiring a circular secretary to collect patients' files from various wards, and controlling them using a standard checklist, nurses' training, and continuous supervision were proposed.