In this paper, we define the rough approximation operators in an algebra using its congruence relations and study some of their properties. Further, we consider the rough approximation operators in orthomodular lattices. We introduce the notion of rough ideal (filter) with respect to a p-ideal in an orthomodular lattice. We show that the upper approximation of an ideal J with respect to a pideal I of an orthomodular lattice is the smallest ideal containing I and J. Further we study the homomorphic images of the rough approximation operators.