Parasitic infections with gastrointestinal (GI) nematodes and liver fluke (Fasciola hepatica) are common causes of reduced productivity in ruminants. In this paper, the results of a voluntary monitoring campaign on helminth infections in Belgian dairy herds are summarized and discussed. From 2009 until 2011, a bulk tank milk sample was collected in autumn and analyzed by antibody-detecting bulk tank milk ELISA's to assess the level of exposure to GI nematodes and liver fluke. The number of farms participating in the survey increased over the years, from 1216 in 2009 to 1731 in 2011. The proportion of herds with high exposure to GI nematodes varied significantly between the three years, from 67% in 2009 over 70% in 2010 to 63% in 2011. The proportion of herds with high exposure to F. hepatica remained stable around 30%. Important regional variations were observed with levels of exposure to GI nematodes increasing from the north to the south of the country, whereas the distribution of F. hepatica was concentrated in the province of West-Flanders, the southern part of East-Flanders, Hainaut and the northern part of Luxembourg. It can be concluded that, when compared with surveys conducted in surrounding countries, the levels of helminth exposure in Belgium can be considered high, especially for GI nematodes. If the aim is to decrease levels of exposure in the future, this will likely require control methods based on altered timings of treatment and changes in pasture management.