The securing and maintaining of alignment between business strategies and Information Systems (IS) strategiesisfrequentlycitedasacriticalconcernofISmanagers. Consequentlyithasbeenrankedasan important issue for IS research agendas over the last decade. Very few empirical studies have, however, been reported with the result h i t there is no firm evidence to support the need for alignment, far less the way that strategies might interact. This paper reports the results of a longitudinal study that examines both IS and business strategies using an extemal-internal alignment model. After four years of data collection and analysis, there is strong support for an alignment model that follows a lead-lag strategy. This implies (hat alignment is not a steady state but will reflect a dynamic and “r”evo1utionary model of change. The alignment and change modeis are described and a future research agenda identified.