The effects of a change in technology on organizational structure and power were investigated in a longitudinal study of the introduction and diffusion of a computerized information system. Employees increased their power and network centrality following the change in technology. In particular, early adopters of the new technology increased their power and centrality to a greater degree than later adopters. Results of cross-lagged correlation analyses suggest that centrality precedes power. While the diffusion process occurred via the network structure, it also imposed changes in the structure. Adoption patterns were found to be more closely related to network structure after the change than prior to the change.