This paper deals with marketing decision support systems (MDSS) in companies. In a conceptual framework five categories of factors are distinguished that potentially affect adoption, use, and satisfaction: external environment factors, organizational factors, task environment factors, user factors and implementation factors. Hypotheses are developed and tested on data from a survey of 525 companies. The factors that determine the adoption of an MDSS are different from the factors that affect the success of an MDSS, once it has been installed. For adoption, support from inside the company, communication and knowledge about MDSS are crucial. For the subsequent success of an MDSS, involvement of the user, sophistication, adaptability of the system and the possibility of direct interaction with the system are important. MDSS are primarily adopted to obtain information and not to upgrade (add value to) existing information. Companies in consumer goods are ahead of companies in the business-to-business sector, but this difference is likely to decrease in the future.