In the present paper, the notion of beta (r, g)-preinvex function is applied to establish some new generalizations of Ostrowski type integral inequalities via Caputo k-fractional derivatives.2010 Mathematics Subject Classification. Primary: 26A51; Secondary: 26A33, 26D07, 26D10, 26D15.Key words and phrases. Ostrowski type inequality, Hölder inequality, Minkowski inequality, power mean inequality, s-convex function in the second sense, m-invex.