Electronic Journal of Differential Equations, Vol. 2012 (2012), No. 138, pp. 1-13. Title: Controllability of nonlinear differential evolution systems in a separable Banach space Authors: Bheeman Radhakrishnan (PSG College of Technology, Tamilnadu, India) Krishnan Balachandran (Bharathiar Univ., Tamilnadu, India) Abstract: In this article, we study the controllability of semilinear evolution differential systems with nonlocal initial conditions in a separable Banach space. The results are obtained by using Hausdorff measure of noncompactness and a new calculation method. Submitted April 19, 2012. Published August 19, 2012. Math Subject Classifications: 93B05, 47D06. Key Words: Controllability; semilinear differential system; evolution system; measure of noncompactness.