In this paper we report on the use of a pre-post-test design to study pre-service secondary mathematics teachers’ mathematical content knowledge in statistics before and after their first university course in statistics. The results show that the participants were successful in the pre-test on items related to sampling, probabi- lity and the general logic of making formal statistical inferences, but struggled with items concerning distributions. Comparing the pre- and post-test reveals an increas- ing average of the participants’ scores in most statistical areas, but that topics like informal statistical inferences and distributions remain challenging for the majority of the participants.