The use and modification of Information Systems Development Methodologies has continued to be an important issue for research and practice as developers struggle to complete largescale IS development projects. Whilst there is a widespread belief that the use of an ISDM is appropriate when developing an information system, a considerable body of evidence exists to indicate that few practitioners actually use methodologies as described. Instead, ISDMs are tailored to create a unique instantiation for each project. This study explores the application of ISDMs in a large global IT company. The paper contributes to the understanding of ISDM application in two ways. Firstly, it identifies two steps in the tailoring process: a deliberate tailoring of the methodology prior to the commencement of a project based on developers’ perceptions of the project and its context; and ad hoc tailoring to meet the real, unfolding development needs of the project. Secondly, it provides a description of the way in which a large, experienced organization using ISDMs has addressed the shortcomings of ISDMs by the introduction of a “meta-methodology”.