A time series model is estimated to identify the interrelation among prices on the international and the EU domestic market for butter. Although the findings were not derived from a causal model, the inspection of the data provides economically reasonable and important insights in structural relationship between international and domestic prices. It can be expected that similar relationships exists for other milk products as well. The fact that international prices in the EU and Oceania are causal for each other is an indication of an integrated market. However, price transmission is not perfect suggesting that competition between the EU and Oceania exists, however, but not as intense as it could be expected for a homogeneous good like butter. The estimates provide further some indication that the EU absorbs price fluctuations form the word market. Interestingly, changes of prices in Oceania have no impact on the domestic EU market. Fluctuations of the EU world market prices, on the other hand, are absorbed to a large extent. The reason for this reaction remains unclear. One explanation may an inappropriate fixing export refunds. Price variations within the EU are also transferred to the international markets.