We carry out an ab initio constant pressure molecular dynamics technique to study the pressure-induced phase transition in KCl. A phase transformation from the rocksalt structure to the CsCl type structure is successfully observed through constant pressure simulation. The rocksalt-to-CsCl phase transformation of KCl is found to proceed via a rhombohedral intermediate state. This phase transition is also analyzed from the total energy calculations. Our transition parameters and bulk properties are comparable with available experimental and theoretical data. Furthermore, we study the behavior of KCl under uniaxial stress. The uniaxial stress causes first a symmetry change to a tetragonal state with space group 14/mmm and then structural failure. (C) 2010 Elsevier B.V. All rights reserved.