A robot including a balancing mechanism or balancer with a compression spring which flexes to compensate for the gravitational moment between an arm assembly and a base of the robot. The compression spring is chosen to have a force-deflection characteristic to account for the gravitational moment and the geometry of the mechanism. The arm assembly has a pivotal connection which pivotally supports the arm assembly on the base of the robot for movement about a pivotal axis. The mechanism can be adjusted for various arm assembly lengths and/or payloads. The mechanism includes a spring support, a connecting rod having a longitudinal axis and connected to the spring support for communicating motion of the spring support to the arm assembly at an attachment point offset from the pivotal axis. The resulting balancing mechanism is relatively compact, which lends itself to robotics applications where space is limited.