Fraud in general is defined as theft by the intentional use of deceit or trickery. In the health care field, it is the intentional use of deceit that separates fraud from honest billing errors. The fraud can be perpetrated by a health care provider, a patient, or both. In the Maryland cases profiled in this article, fraud involved the forgery of receipts for equipment purchases that were never made and the altering of pharmacy supply receipts submitted in paperwork to the State health plan. In the latter case, the patient was on disability status with the State's workers' compensation program. Dates were altered and additional items were reported on receipts and submitted both to the workers' compensation fund and the private insurance carrier. This article's general discussion of types of health care fraud focuses on billing for nonrendered services; fraudulent coding for a service that is more expensive than the one actually rendered; the "mischaracterization" of a service to make it qualify for insurance coverage; the performance of unnecessary medical services; quackery and sham cures; and "kickbacks." In attempting to counter health care fraud, a prosecutor can start by establishing a liaison with the Special Investigations Units (SIU's) of insurance companies that do business in the State. An SIU or its equivalent acts as an in-house fraud detection and investigation unit for insurance companies. Similarly, State and private workers' compensation bureaus often have an intelligence base regarding suspect providers; they can supply evidence that would form the basis for a criminal charge. Further, State licensing boards in the various medical professions can often be a source of information on problem providers. In many jurisdictions, there are health care fraud task forces that have been organized by the local U.S. attorney's office. At the national level, the National Health Care Anti-Fraud Association is a private/public partnership against health care fraud and an excellent resource. It provides a variety of investigative support resources, as well as a number of education and training programs geared toward the prosecution and investigation of health care fraud.