Objective: This study aimed to assess the diversity of extemporaneous preparations, identify the prevalent formulations, and highlight the challenges and opportunities for standardization and improvement of extemporaneous preparation practices. Methods: A survey was conducted among 88 Thai hospitals representing the public and private sectors. The questionnaire gathered information on general hospital characteristics, detailed aspects of extemporaneous compounding, and the specific extemporaneous formulations used. Results: The survey revealed significant variations in extemporaneous preparations among Thai hospitals, with oral liquids, semisolids, and eye preparations commonly employed. The primary oral liquid formulations used were suspensions, syrups, and solutions. Specific medications frequently used in extemporaneous preparations were also identified. The challenges encompassed space, personnel, skills, raw materials, equipment, standardized formula information, preparation process information, funding, and other factors. Conclusion: A survey among Thai hospitals revealed significant variations in extemporaneous preparations in 88 participating hospitals. Common formulations used in extemporaneous compounding include oral liquid preparations, such as suspensions, syrups, solutions, semisolid preparations, and eye preparations. Stakeholder involvement, implementation of standardized operating procedures, resource allocation, comprehensive training programs, and collaboration among hospitals, pharmaceutical companies, and regulatory agencies are recommended to enhance extemporaneous compounding practices.