Illegal billing practices encompass a range of deceptive or fraudulent activities aimed at unlawfully obtaining reimbursement from healthcare payers. These practices may include upcoding, where healthcare providers bill for more expensive services than those actually rendered, unbundling, which involves billing separately for services that should be billed together as a single procedure, and billing for services not provided or medically unnecessary procedures. Other illegal billing practices include kickbacks, where providers receive financial incentives in exchange for patient referrals or prescribing specific treatments, and balance billing, which occurs when providers bill patients for amounts beyond what their insurance covers in violation of contractual agreements. These practices not only defraud insurance companies and government healthcare programs but also result in financial harm to patients and undermine trust in the healthcare system. Therefore, stringent enforcement of anti-fraud regulations and robust oversight mechanisms are essential to combat illegal billing practices and safeguard the integrity of healthcare billing processes.