Hand-checking in basketball is a personal foul describing illegal contact by a defender who uses their hands to impede the movement of an opponent that possesses the ball. A hand-checking foul will give the opposing defender a single foul and will result in a dead ball followed by an inbound pass for the offense. If the team is in the bonus, a hand-checking foul could also lead to free throws.
Most referees will not call hand-checking if the defender uses his hands one time; hand-checking fouls are generally called when a single defensive player is continuously making contact with their hands throughout the game. Hand-checking is typically called at the top of the key because this is where defenders will be matched up against guards or ball handlers. Hand-checking is generally not called in the low post area because defenders are allowed to make contact with their hands on opponents who have their back to the basket.
Hand-checking, or defensive contact with the hands, used to be allowed in the NBA prior to 2004. However, the NBA changed their hand-checking rules to make this type of contact a foul. Now, if you are hand-checking at any level of basketball, you will be called for a foul. Hand-checking is most similar to a reach-in foul, which is also a common defensive foul.