We are given data α1, . . . , αm and a set of points E = {x1, . . . , xm}. In this paper we address the question of conditions ensuring the existence of a function f satisfying the interpolation conditions f(xi) = αi, i = 1, . . . ,m, that is also n-convex on a set properly containing E. We consider both one point extensions of E, and extensions of E to all of IR. We also determine bounds on n-...