Abstract. For several embedded surfaces with zero self-intersection number in 4-manifolds, we show that an adjunction-type genus bound holds for at least one of the surfaces under certain conditions. For example, we derive certain adjunction inequalities for surfaces embedded in mCP 2 #n(−CP 2 ) (m, n ≥ 2). The proofs of these results are given by studying a family of Seiberg-Witten equations.