Background: Informal payments were reported in Bulgaria before and after the introduction of formal co-payments for services included in the basic benefits package in 2000. The aim of our study was to establish the current scale and type of informal payments, as well as public attitudes towards these payments. Methods: A nationally representative survey of 1003 individuals was conducted in Bulgaria in July 2010 using face-to-face interviews based on a standardized questionnaire. Respondents were selected through a multi-stage random probability method. The questionnaire included questions on total informal payments (in cash and in kind) for health services used by the respondent during the preceding 12 months. Results: About 13% of users reported informal payments for outpatient visits and 33% of users reported to have paid informally for hospitalizations. The average amount paid informally for inpatient services was nearly twice higher than that for outpatient services. More than 50% of the sample had negative attitudes towards informal payments in both cash and kind, but about 27% of respondents had a positive attitude towards giving gifts in kind. Regression analysis showed that respondents with higher levels of education had more negative attitudes towards informal cash payments. Positive attitudes towards gifts in kind were more often stated by citizens of larger cities. Conclusion: Informal payments continue to exist in Bulgaria irrespective of the formal co-payments introduced in 2000. Although the problem has been recognized in Bulgaria, policies should aim to eliminate the underlying structural reasons for such payments.