This paper focuses on the impact of digitalization and marketing automation on the “scope” of the heuristics adopted in the marketers’ decision-making processes. The “scope” refers to the decision-making contexts in which the use of the heuristic rules is diffuse and is effective. More precisely, “scope" is (the extension of) the field in which a heuristic can be applied (successfully). The article is based on evidence collected through ethnographic interviews with twenty-three experienced marketers to discuss the impact of marketing automation (...) on the scope of heuristic rules in decision-making. The marketers interviewed make extensive use of heuristics to manage their tasks as emerged from previous exploratory research. The paper discusses how the field of application of marketing experts' heuristics evolves as result of the digitalization and in particular of the use of automatic marketing systems. The adoption of the new automatic marketing tools modifies the task environment and the field of use of the traditional heuristic rules, but heuristics remain fundamental in the definition phase of the inputs for the automatic marketing systems, or for the interpretation of the output and therefore for the control of the marketing automation. The paper clarifies the concept of scope of heuristics and offers a rich description of the impact of marketing automation on scope. (shrink)