This paper describes some of the complex relationships that exist between R&D (research and development) and M&S (marketing and sales). Factors impacting R&D and M&S are analysed such as company size, company age, wishes for changes in the individual company, etc. Seven propositions are presented. One specific finding from the study is that, for different product life cycles (PLCs), R&D and M&S often counteract so that when R&D spendings are allowed to increase, M&S spendings are reduced and vice versa. Management of technology (MoT) is not an exact science, and therefore the paper focuses on magnitudes of order instead of decimals in R&D and M&S expenditures for individual companies depending on branch, and differing situations. One important result of the investigation is that short PLCs means larger R&D spendings, and vice versa. (C) 1998 Elsevier Science Ltd. All rights reserved.