The purpose of this paper is to provide an insight into the various types of wastes in IT service system from the perspective of lean management. A study of 12 IT support service lines was carried out with an objective to identify and categorise waste/non-value added activities in IT services. The waste activities have been classified into 13 groups: defects, re-invention, unnecessary motion, waiting, over processing, inventory, resource inefficiencies, hand-offs, external quality enforcement, processing inefficiencies, lack of system discipline, ineffective communication and recurring incident. It is quite possible that some of the identified wastes may have inter-relationship or dependency within them. However, such relationship among the wastes was not covered in this study. The paper presents a methodology for identification and classification of wastes in IT support service system. This categorisation would be useful while applying lean principles to IT support service systems. Copyright © 2011 Inderscience Enterprises Ltd.