An illegal form of defense in basketball in which a defending player uses one or both of his hands or his arm to impede the forward or lateral movement of an offensive player.
Hand-checking is typically considered a foul if the defender continually uses his hands to impede the progress of any offensive player. As contact is frequent during a game of basketball, officials will not often call a hand-checking foul if the contact between a defender and an offensive player is incidental. Hand-check fouls are mostly called against defenders assigned ball handlers, and therefore usually occur out on the perimeter or at the top of the key.
The hand-check penalty was introduced by the NBA at the outset of the 2004-2005 season, primarily as a way to allow the offense more freedom of movement and to keep games running more smoothly.