This paper examines the following question: How do government organizations become more “post-bureaucratic” with web-based IT projects? It draws on evolutionary thinking to conceptualize processes of change in government organizations as involving sequences of variation, selection, and retention as well as to identify various sources of change: internal ones (e.g. administrators), as well as external ones (e.g. technological innovations and institutional pressures). The paper relates findings from four in-depth qualitative case studies of web-based IT projects in different government organizations. The interpretation of these findings helps expand the evolutionary conceptualization by suggesting how different sources of change interact in the change process and variously affect different stages of the evolution.