This paper presents the main results from case studies in 10 Swedish manufacturing companies concerning their product costing. The main purpose of the study is to find out what models of product costing the companies use, what allocation bases are applied. Several questions have been asked to the companies: What is the purpose of the product costing? Is a special product costing used for inventory valuation? Is full costing or variable costing used? How are depreciation costs and cost of capital treated? Is some sort of activity-based costing used? If so, which are the cost drivers? The study is a case analysis, no questionnaires are used. The study presents arguments that a separation of product costing in ''Activity-Based Costing'' or ''traditional costing'' is not possible, but also that more ''ABC-thinking'' is necessary.