Introduction: Since 2013, in Iran's health care, the contribution of direct payments for health-care services was estimated more than 50 % of all expenditures. In May 2014, Iran's health-care reform was established to improve health services quality and reduce patients' out-of-pocket payments <10% in urban and 5% in rural areas. Therefore, the purpose of this study is to investigate unmet costs (those which are not covered either by the insurance companies nor the recent reform coverage mentioned in Sections 1.2.2 and 1.2.1, Article 6 of the Health Minister Reform Guideline) in the inpatient billings within the first 5 months from the reform implementation. Methods: This study was conducted as a cross-sectional research in the second half of 2014 on the selected hospitals in Isfahan Province. Data were collected by investigating 97,000 inpatients' billing records issued by 28 hospitals affiliated to Isfahan University of Medical Sciences using census method. Results: Findings of the study showed that the average of unmet costs paid by the inpatients constituted 21.8% of the total billing costs in 28 hospitals, and the average unmet costs paid by each patient was 1,903,832 Rials. Conclusion: Considering the definition of unmet cost in the context of health-care reform guideline and hospitals' problems in providing some costly services, drugs, and medical equipment (that were not covered by insurance organizations and the reform scheme) within the obligations of the reform, it is necessary to review these obligations and further interact with insurance companies about expanding the coverage to some costly services required by the patients.