A subset S of a group G is called an Engel set if, for all x, y is an element of S. there is a non-negative integer n = n(x, y) such that [x, (n)y] = 1. In this paper we are interested in finding conditions for a group generated by a finite Engel set to be nilpotent. In particular, we focus our investigation on groups generated by an Engel set of size two. (C) 2011 Elsevier Inc. All rights reserved.