This paper investigates whether responses to choice experiments (CEs) are subject to ordering anomalies. While previous research has focussed on the possibility that such anomalies relate to position in the sequence of choice tasks, our research reveals that the particular order of tasks matters. Using a novel experimental design that allows us to test our hypotheses using simple nonparametric statistics, we observe ordering anomalies in CE data similar to those recorded in the dichotomous choice contingent valuation literature. Those ordering effects operate in both price and commodity dimensions and are observed to compound over a series of choice tasks. Our findings cast serious doubt on the current practice of asking each respondent to undertake several choice tasks in a CE while treating each response as an independent observation on that individual's preferences.