The Belgian pig production has been confronted with stagnating prices since the start of the century. While several studies have investigated the financial structure of the pork production chain, it remains unclear whether excessive market power from slaughterhouses, or meat retailers plays a role. Market power studies can reveal some of the market dynamics in this setting, but this type of research has not yet been applied to the Belgian pork market. This paper looks at potential oligopolies and oligopsonies in the pork production sector. A new model is build to focus on market power dynamics in the market for live pigs. This model distinguishes horizontal and vertical market power parameters both for pig farmers and for slaughterhouses. The results follow from an empirical application using slaughterhouses data for the period 2002-2011. The potential reasons and consequences of these market powers are discussed.