The overall outcome of IS planning efforts is determined by how effectively the planned strategies are implemented in order to realize the envisaged strategic benefits. This empirical work on IS plan implementation relates the effective implementation of IS plan with IS performance in the Indian context. Based on three case studies from diverse industry segments, we discuss the five important parameters of IS plan implementation- top management commitment, implementation responsibility, IS plan characteristics, user involvement, role of IS function that determine the implementation effectiveness and eventually the IS performance. Based on the analysis, we present a set of key learnings for developing countries, along with implications for future research.