In this paper, another population based firefly algorithm in combination with load incremental algorithm is proposed to find maximum loadability limits of power system. Firefly algorithm is a nature inspired algorithm proposed by X.S.Yang [19-21]. The algorithm is based on the behaviour of fireflies. The algorithm is sufficiently random in nature and produces optimal solution in less computational time. It has been applied successfully on NP hard problems [22-32]. It has been found that firefly has ability to provide better solution than other existing methods in various engineering applications viz. economic dispatch [ 22-23], travelling salesman problem [24], job scheduling [25], automatic generation control [26], image compression [27], highly nonlinear multimodal design problems [28] and multiobjective problems [29]. Authors found that FA is consistent and has better performance than existing evolutionary algorithms [30].