The EU Emissions Trading Scheme (EU ETS) is the first large-scale multi-national greenhouse gas (GHG) trading program and a central instrument of European climate policy. The EU ETS market is still young, but growing rapidly. In the last two years, the average daily trading volume at the ECX has increased enormously, from 4 million tCO2 (2007) to 20 million tCO2 (March 2009). From over 11.000 installations covered by the EU ETS, 1.660 are located in Germany being responsible for almost 50 % of national green house gases. One third of the installations under the trading scheme belong to energy intensive industry sectors and two thirds to the energy sector. Compared to 499 million tCO2 in the years 2005 - 2007 the total number of allowances to be issued within the second trading period has been reduced to 452 million tCO2 annually. With this tighter emissions cap, the relevance of the carbon market for the covered firms can be expected to increase. Despite its high importance for both market participants and stakeholders, the data basis concerning developments and expectations in supply and demand as well as prices of emission allowances and emission reduction certificates is still lagging behind. The KfW/ZEW CO2 Barometer – a survey among German firms covered by the EU ETS and international carbon experts developed in cooperation between KfW Bankengruppe and the Centre for European Economic Research (ZEW) – intends to close this gap.