Despite of the recent dynamics in green building movement in Central and Eastern Europe (CEE), there is little scientific evidence of the actual demand for green office space and market value of green building certificates. Contrary to the US and UK, where there is enough market data for hedonic studies that demonstrated the positive effect of Green Building certificates on rents, occupancy level and transaction prices (for comprehensive review see: Falkenbach et al., 2010), the green office stock in CEE is still too small for revealed preference analysis. Therefore, the current study uses a stated preference data and confronts office tenants with hypothetical choices in order to assess demand for sustainable office space. The paper presents empirical results from web-based choice-based conjoint experiment in four CEE countries: Austria, Poland, Slovakia, and Ukraine. In the experiment we confront office tenants (decision makers in companies) from Krakow, Warsaw, Wien, Bratislava, and Kiev with hypothetical options for office alternatives. One of the characteristics taken into consideration is the availability of a Green Building certificate. As the result we estimate willingness-to-pay (WTP) for green building certificate in each of CEE countries in the study. We also address the question of differences in WTP between countries in the study.