Introduction. A subsequent, yet a significant amendment to the Public Finance Act, which has been effective since January 1, 2010, extends the list of sector units obliged to implement internal auditing. This Act also specifies the healthcare sector units which need to implement auditing. The function and development of internal auditing, places it in the organizational structure of the public finance sector units. Aim. This work aims to discuss the binding internal audit regulations, instructions and standards as well as the principles of internal auditing in the healthcare sector units. Discussion. The author discusses the legal basis binding for internal auditing in the healthcare sector and the organization of the audit committee in the Ministry of Health. The legal basis concerning qualification requirements for internal auditors is presented. The role, objectives and fundamental rules of internal auditing in the healthcare sector units are defined. The author also presents the documentation involved in internal audit. Conclusions. Public sector internal auditing is and will continue to be constantly improved since it is introduced, i.a., by virtue of the amended Public Finance Act effective as of January 2010 as well as the new version of the International Standards for the Professional Practice of Internal Auditing put in practice in the Public Finance Act in 2009. Internal auditing becomes obligatory in more and more public finance sector units, including the healthcare sector units, thus it is necessary and efficient for the public finance sector operation.