Background: Knowing customers' level of satisfaction is relevant to improve and provide quality health care services. In the clinical laboratory, monitoring customers' satisfaction is an important indicator of the quality management system and required by international laboratory standards. However, in Ethiopia, there has not been baseline data about the satisfaction level of patients' with laboratory services at the national level. The aim of this national level survey was to assess patients' satisfaction level with laboratory services at public hospitals in Ethiopia. Methods: A national survey was conducted using an institutional based cross-sectional study design was employed from 01 to 30 November 2017. A total of 2399 patients were selected randomly from 60 public hospitals. Data was collected using structured questionnaire, entered in Epi Info and analyzed with SPSS software. Multiple logistic regression model was fitted to identify predictors of patients' satisfaction with laboratory services. A p-value of less than 0.05 was taken as statistically significant. Result: Overall, 78.6% of the patients were satisfied with the clinical laboratory services. Patients were dissatisfied with cleanness of latrine (47%), long waiting time (30%), clear and understandable advisory service during specimen collection (26%), adequacy of waiting area (25%), easy accessibility of laboratory (19%) and latrine location (20%), availability of requested service (18%), unfair payment of service (17%) and missing of result (12%). The educational status (P = 0.032), and distance (P = 0.000) were significantly associated with client overall satisfaction level. Conclusion: Most laboratory patients' were satisfied with the service provided by public hospital laboratories in public hospitals in Ethiopia. However, patients' were dissatisfied with the accessibility of sites, adequacy of waiting area, cleanness of latrine, long TAT, communication, missing of results, availability of requested service and cost of service. Therefore, responsible bodies in each level should act on the identified gaps and improve the need of patients in each hospital laboratory. In addition, all hospital laboratories should conduct a satisfaction survey and meet the needs of laboratory patients.