Taking successful measures against international trade in counterfeit goods requires a thorough understanding of the characteristics of the illicit market. However, the clandestine nature of the phenomenon makes an investigation a challenging exercise. Even the validity of existing estimates on its size seems highly questionable. Against this background, this contribution proposes a framework for estimating the extent of counterfeit trade which relies on various public data sources. We apply our framework to the examples of the North-American and the European market and draw conclusions on the share of counterfeits among world merchandise trade.