In the topological sum of pairwise disjoint topological spaces, we inves- tigate topological properties of the following generalized closed sets: preclosed sets, semi-closed sets, -closed sets, g-closed sets, sg-closed sets, gs-closed sets, gp-closed sets. Moreover, we have a characterization of some generalized compact topological sum. The results are proved by using a unified concept in the sense of [23] [13] [22] (eg., [17]) (cf. Section 2 and Section 3 below); we have generalized versions of main results.