Police corruption is a form of police misconduct in which a law enforcement officer breaks their political contract and abuses their power for personal gain. A corrupt officer may act alone or as part of a group. Corrupt acts include taking bribes, stealing from victims or suspects, and manipulating evidence to affect the outcome of legal proceedings (such as in a frameup). Police corruption challenges the human rights of citizens, and can undermine public trust in the police when uncovered or suspected.

Soliciting or accepting bribes in exchange for not reporting organized drug or prostitution rings or other illegal activities and violations of law, county and city ordinances and state and federal laws.

Bribes may also include leasing unlawful access to proprietary law enforcement databases and systems.

Flouting the police code of conduct in order to secure convictions of civilians and suspects—for example, through the use of falsified evidence. There are also situations where law enforcement officers may deliberately and systematically participate in organized crime themselves.

Selective enforcement

In most major cities there are internal affairs sections to investigate suspected police corruption or misconduct, including selective enforcement, but there are situations where Internal Affairs also hides departmental and individual corruption, fraud, abuse and waste by individual officers, groups of officers or even unwritten departmental policies. There are also Police Commissions who are complicit in the same cover-ups, often to hide internal and departmental problems, both from public view, and also from inter-departmental reviews and investigations. Certain officers can be fired, then rehired by petition after they accrue enough signatures, often from the very criminals and violators from whom corrupt officers have garnered previous favors in exchange for officers "turning a blind eye", resulting in selective enforcement of violations being deterred, but actually promoted.

Similar entities include the British Independent Police Complaints Commission. Police corruption is a significant widespread problem in many departments and agencies worldwide.

It is not possible to measure the level of corruption in a country. Surveys of police officers, citizens and businesses can be used to provide estimates on levels of corruption. These are often inaccurate, as respondents involved in corruption are reluctant to provide any information implicating themselves in criminal activity. Despite this limitation, information collected from International Crime Victim Surveys and surveys conducted by the Global Corruption Enumerated Barometer can be used to estimate the level of police corruption.