There is presently an international discussion among statistical institutes, reserve banks etc. about the feasibility of replacing true price indices of exports and imports by unit value indices. For the very few countries, such as Germany, providing both indices on a monthly basis this would mean to give up a (costly) compilation of P-indices. The paper shows that this would be unwise. It aims at exploring the still not well understood methodological differences of both types of indices, and it is also reporting some empirical results of a research project in cooperation with the German Bundesbank.