Factors influencing the success or failure of an information system (IS) have been discussed frequently in the literature. This study identifies several additional factors and proposes that the existing ones be classified into eight different dimensions. These encompass, not only the system aspect, but also the human aspect of IS success (ISS). The study further uses data from past ISS studies and also those collected from a field survey to analyze the differences in the perceived importance of ISS factors between four groups of subjects from North America, namely, the user staff, the IS staff, and the managers of the two groups. It reveals that the rank orders of ISS factors between IS staff and IS managers and between user staff and user managers are not significantly different. However, the rank orders between IS personnel and user personnel are significantly different. Based on these, the top and the least important ISS factors are identified. The findings have several implications for IS management practice.