Background: Patients and physicians are considered primary customers of laboratory services. Therefore, assessing customer satisfaction with laboratory services is an essential indicator in improving the quality of laboratory services. Objectives: This study measures the level of satisfaction of physicians and patients who avail of the clinical laboratory and phlebotomy services, respectively, at the outpatient department (OPD) in King Abdullah Medical City (KAMC), to evaluate the possible issues and carry out corrective actions. Methods: A cross-sectional survey to evaluate the level of satisfaction using a modified patient and physician questionnaires, the patients were randomly selected and interviewed in phlebotomy areas at the outpatient and chemotherapy clinics. A paper-based questionnaires were distributed to all physicians all available physicians in KAMC who were regularly requiring laboratory investigations. The collected data were coded, entered, and checked for outliers or missing data and analyzed using the SPSS statistical package version 21. Results: A total of 435 patients were interviewed and their mean satisfaction was 4.51±0.32 out of 5. Respondents were satisfied with the Availability of laboratory tests. However, they were dissatisfied with Explanation of the phlebotomy cautions by the phlebotomist (75.4%). Twenty eight percent of physicians (132) participated, their mean satisfaction rate was 3.6±0.7 out of 5. The greatest satisfaction rate was related to critical results notification and the communication with laboratory personnel. Physicians were most dissatisfied with both specimen delivery process and incorrect test results. Conclusion: Both customers were satisfied with the laboratory service provided for them. Factors as "Explanation of the phlebotomy process by phlebotomist" and "specimen collection and delivery process" received lowest satisfaction score for patients and physicians respectively. Therefore, improving them is required to meet the needs of the customers and gain their satisfaction regarding the service.