While the literature provides considerable guidance about the factors and conditions that influence the use of computers and management information systems, far less is known about the factors and conditions that lead to the use of marketing information systems (MkIS). The paper reports on the results of an investigation of the determinants of Marketing Information Systems (MkIS) usage based on responses from 126 MkIS users. A multivariate model was developed and tested using analysis of covariance. Several specific propositions are proposed and tested. The results indicate that MkIS usage (as measured by frequency of use, number of information technologies in use, number of years of system usage experience and reported usage time) is influenced by factors such as task exceptions, task complexity, organisational maturity, organisational situations, user gender, organisational level, cognitive style, familiarity and perceived usefulness. Based on the research findings, several recommendations are made to improve the use of marketing information system. This paper is divided into five sections. The first section provides an introduction and outlines the research objectives of this paper. Section two reviews the literature and develops a conceptual model. The research approach and instrument validations are discussed in section three. Section four discusses the results and their implications for system designers, vendors, researchers and top management. The concluding comments with the limitations of this study and recommendations for further research are discussed in the last section.