The aim of this paper is to present the process of informatization of medical biochemical laboratory (MBL) and the impact of information systems on the organization of work and optimization of the work process with a presentation of possible technological changes that can still be introduced into the existing system. Data in primary and secondary health care and the connection of data with the hospital information system and laboratory information system are presented. The development of the hospital information system, the current state and application in everyday work and the connection of hospital information system with the laboratory information system are presented. Information systems in laboratories are presented - the development and presentation of the current state of LIS, the positive and negative sides of LIS in everyday work, the contribution of LIS to the development of quality systems and quality management and additional opportunities provided by LIS. The research was conducted in the General Hospital Zabok and the Hospital of Croatian Veterans and in the department of that hospital - Medical Biochemical Laboratory. The research consists of a theoretical and an empirical part. The empirical part of the research is based on primary data obtained from the survey questionnaire, LIS verification on the analysis method and statistical method, and autovalidation protocols on the measurement method and statistical method. The theoretical part is based on secondary data, scientific and professional literature and instructions for hospital information system and LIS users. Possible technological solutions for the improvement of the informatization system in health care, especially in medical laboratories, are presented. Research has shown that without advanced information technology that is constantly evolving and motivated and educated staff can not organize work in health care institutions, especially in medical biochemical laboratories that produce many numerical and administrative data that require quality and fast IT support.