This paper examines the association among product diversity, advanced manufacturing technology, and activity-based costing adoption. Current theories strongly suggest that product diversity is a major determinant of the demand for ABC systems. To date, the results of empirical research on the relationship between product diversity and ABC adoption, have mainly accomplished in advanced countries, have generally been inconclusive. These results illustrate that there either may be no strong relationship, or that methodological issues may have constantly prevented researchers from achieving definite findings. In addition, this research completed in Iran, as a developing country, uses a dataset of survey responses from 136 Iranian manufacturing firms in the Tehran Stock Exchange, with 23. 84% response rate, re-examines the relationship between product diversity and ABC adoption. This study by Improving upon the measurement of product diversity and distinguishing between ABC adoption as well as ABC use, examines whether the relationship is curvilinear or not, and/or is moderated by usage of AMT. This paper contributes to the literature by showing that product diversity, on average, is positively related to both ABC adoption and ABC use; namely, these relationships are linear. Furthermore, the relationship between product diversity and ABC use is not moderated by usage of AMT-that is-there is no interaction effect between AMT and product diversity. However, AMT is positively related to ABC use.