In a preferred embodiment, there is provided an adjustable roller bracket assembly for a belt conveyor system, and which comprises a first end portion, a second end portion, and an adjustment mechanism connecting the first and second end portions, the first end portion being for attachment to a system frame, the second end portion being for rotatably engaging a roller at an axial end thereof, and the adjustment mechanism being operable to permit selective movement of the second end portion relative to the first end portion against frictional resistance therebetween to effect adjustment of a rotational axis of the roller.