It is known that roll coating is formed on work rolls in cold rolling of stainless steel, copper alloys or aluminum alloys. It affects surface properties of rolled strip, rolling characteristics and amount of wear debris formed. By the way, actual rolling mills have back-up rolls, which are equipped in order to reduce the deflection of the work rolls. In this study, cold rolling of Al–Mg alloy A5182 is conducted in laboratory to investigate the effects of back-up rolls, on the rolling lubrication with a pair of back-up rolls which have groove at the center of the barrel. The backup roll does not contact with the roll coating on work roll when using the grooved backup-roll. As a result, it is found that the attainable maximum reduction in thickness is reduced by approximately 10 point compared with the case using normal flat back-up rolls. In addition, cold rolling of aluminum A1050 is conducted to investigate the effects of back-up rolls, on amount of wear debris formed in rolling lubricant. As a result, it is found that in the case of normal flat back-up rolls, the amount of wear debris is pronounced than the case of grooved back-up rolls.