The aim of our research is to seek an explanation for contradicting results in innovation studies that use technological, organizational and environmental (TOE) factors to explain the adoption of Information Technology (IT) innovations. We do this by taking into account the type of innovation, specifically product and process innovation. We carried out a meta-analysis of 35 IT innovation adoption studies. The results show that five factors consistently affect the adoption decision for both product and process innovations, namely relative advantage, compatibility, top management support, organizational readiness, and competition. Two factors, namely organizational size and external pressure, showed significant effect for product innovations, but not for process innovations. Accordingly, we conclude that distinguishing product and process innovations can be useful in studying the influence of TOE factors in IT innovation adoption.