Exploitation of women in the sex industry is the best known but probably not the most common outcome of trafficking in human beings. Still, trafficking for labour exploitation gets less attention from policy makers, the police and researchers. The legal framework allows dealing with trafficking for labour exploitation, but the prosecution of such cases is still in its infancy. In this contribution we focus on labour exploitation. We first present the legal framework. Then we go into the lack of knowledge in this area, followed by what we do know about risk sectors, victims, and what makes them vulnerable for exploitation. Focussing on the Netherlands, we describe the perpetrators and the difficulties in investigating and prosecuting trafficing cases in general and labour exploitation in particular, rounding off with some general conclusions.