This paper takes a look at the political issues involved in the implementation of health information system (HIS) in resource constrained countries. By doing a comparative case, we attempted to understand how two different implementation processes took shape in two countries – Tanzania and Vietnam using Actor network theory (ANT) as our analytica lens. The study suggests that by mobilizing an appropriate number of actors, the HIS implementation as a network building process can earn its effect as a hub to attract other important actors that are still reluctant to join the initiative. Furthermore, the paper argues for the need to make use of detours and pay special attention to the marginal groups of actors as siginificant approaches in the network building process in resource constrained settings.