Abstract. In this paper we obtain a generalization of Matkowski's fixed point theorem and Istrȃţescu's fixed point theorem concerning convex contractions. More precisely, given a complete b-metric space (X, d), we prove that every continuous function f : X → X is a Picard operator, provided that there exist m ∈ N * and a comparison functionfor all x, y ∈ X. In addition, we point out that if m = 1, the continuity condition on f is not necessary and consequently, taking into account that a metric space is a b-metric space, we obtain a generalization of Matkowski's fixed point theorem. Moreover, we prove that Istrȃţescu's fixed point theorem concerning convex contractions is a particular case of our result for m = 2. By providing appropriate examples we show that the above mentioned two generalizations are effective.2010 Mathematics Subject Classification: 54H25, 47H10