1 0 g(t)y(t) dt, y (1) = 0, where the weight functions a(t), b(t), and ω(t) change sign on [0, 1], and g(t) ≡ 0 and h(t) ≡ 0 on [0, 1]. By constructing a cone K 1 × K 2 , which is the Cartesian product of two cones in space PC[0, 1], and applying the well-known fixed point theorem of cone expansion and compression in K 1 × K 2 , we obtain conditions for the existence and multiplicity of positive solutions of a nonlocal indefinite impulsive differential system. An example is given to illustrate the main results.