The “regularity” of a Boolean function can be exploited for decreasing the cost of its representation or its minimization time. In this paper we study a class of regular Boolean functions called 2D-reducible. We prove that 2D-reducible functions are partially symmetric and we exploit this property to propose a variable ordering for their OBDD representations. The detection of such variable ordering is very efficient since it is polynomial in the SOP representation of the Boolean function.