Medical laboratory service is an integral part of public health service. Medical specialist plays the role in the implementation of laboratory services as the person in charge or coordinator for examinations, testing, and laboratory personnel management as well as act as a daily controller to ensure quality medical laboratory services. Nonetheless, there is a possibility of medical errors to take place including providing lab results, diagnosis, and treatment done by a doctor. As a result, it is extremely important and needed as regards who can be held accountable for such medical lab errors in hospitals. The research design applied in this paper is legal research which focuses on examining legal norms in an applicable statutory regulation relevant to the subject matter. The research aims to analyze the authority and legal liability of the medical specialist in charge of labs in hospitals. The research found that the approval of a medical specialist as the person in charge of labs is carried out on a strong legal framework, and the clarity of the rules regarding the expected duties and obligations of the medical specialists significantly contributes to the improvement of the labs’ services alongside medical and legal liability. Consequently, when an error occurs, the hospital is liable for all losses caused by negligence committed by personnel in hospitals, which is in line with the Indonesian Act on Hospital Law Article number 46. Considering that the legal relationship between doctors and patients in health services at hospitals is contractual, the patient is able to take a legal remedy to file a civil lawsuit to the local District Court for the liability for the loss caused by unlawful acts for the fact that hospitals do not provide quality, safe, and effective medical services that prioritize the patients’ interests and safety

Keyword: Health Law, Medical Specialists, Medical Laboratory, Hospital