We introduce the notions of maximal and minimal open sets in bitopological spaces and obtain some properties of them. In contrary to maximal and minimal open sets in topological spaces, we observe that maximal and minimal open sets in bitopological spaces behave differently. The maximal and minimal open sets in a bitopological space under the operations of union and intersection respectively sometimes become slightly different types of maximal and minimal open sets in that bitopological space. We also obtain results concerning an asymmetric minimal open set on a subspace of a bitopological space.