Modern highly developed society pays more attention to health services quality improvement, along with the quality improvement of laboratory services. Due to extreme importance of getting accurate and reliable laboratory information, as a very important factor in a process of patient treatment, quality of every phase of work should be controlled and should meet international standard requirement ISO 15189 which is accepted as the Croatian standard HR EN ISO 15189. Apart from insuring quality of laboratory services, ISO regulates reviewing patients' feedbacks. Since a patient doesn't have enough knowledge to evaluate quality and considering general issue with measurement of service quality which is variable, intangible and heterogeneous, it was necessary to use one of the designed models for measuring quality of service activities with the aim of establishing dimensions that affect patients' satisfaction. In this research we used SERVPERF (Service Performanse) model for measuring service quality according to the authors Cronin and Taylor from year 1992, and we confirmed its applicability for examination of patient satisfaction with Medical-Biochemistry laboratory services including smaller changes and application of newly designed dimensions; Space, Service and Employees. We questioned patients' satisfaction with laboratory services and concluded that they are satisfied. Also, we concluded that the variables of the dimension Space had the most impact on patients' dissatisfaction and should be used as a focus for improvements in future, as for the variables of the dimensions Service and Employees, they had the most impact on patients' satisfaction and therefore contributed to patients' overall satisfaction.