To make more effective and efficient media planning decisions, we need insight into media context variables that influence the effects of the advertisements embedded in these media. The research involved in achieving this insight has to fulfil three essential requirements: (i) inclusion of several media types (television, radio, print, etc.); (ii) inclusion of a variety of media context variables; and (iii) a real-life context instead of an experimental situation with forced exposure. We developed an instrument - the Media Experience Monitor - that meets these requirements and used it to gather data from a representative sample of the Dutch population for eight media. The instrument was used in the second part of the study to examine the interaction between experiences of advertising and the carrying media for all eight media included in our study. The results show that the strength of the interaction differs: the strongest relationships were found for print media, and the weakest for television and cinema. Recommendations are also given for applying the Media Experience Monitor in media planning practice.