Background: The existence of quasi-formal and informal payments in the Ukrainian health care system jeopardizes equity and creates barriers to access to proper care. Patient payment policies that better match patient preferences are necessary. We analyze the potential and feasibility of official patient charges for public health care services in Ukraine by studying the patterns of fee acceptability, ability and willingness to pay (WTP) for public health care among population groups. Methods: We use contingent valuation data collected from 303 respondents representative of the adult Ukrainian population. Three decision points were separated: objection to pay, inability to pay, and level of positive non-zero WTP. These decisions were studied for relations with quality profiles of the services, and socio-demographic characteristics of the respondents and their households. Results: The likelihood to object to pay is mostly determined by the quality characteristics of the services. Objection to pay is not related to corresponding behavior in real life. The likelihood of being unable to pay is associated with older age, lower income, and a larger share of household members with no income. The level of positive WTP is positively related to income (+7% per 1000 UAH increase in income) and is lower for people who visited a doctor but did not pay (-22%). Conclusions: Rather substantial WTP levels (between 0.9% and 1.9% of household income) for one visit to physician indicate a potential for official patient charges in Ukraine. User fees may cover a substantial share of personnel cost in the out-patient sector. The patterns of inability to pay support well designed exemption criteria based on age, income, and other aspects of economic status. The WTP patterns highlight the necessity for payments that are proportional to income. Other methodological and policy implications are discussed.