Commercial properties play a central role in economics. They are the most important real estate investment class for institutional investors, even more important than the housing market. On the other hand corporations and self-employed people consider commercial properties as input factors, for which especially the quality and costs matter. Despite the fact, that estate agents, consulting firms and banks publish market reports on a regular basis, the commercial properties market lacks behind other investment markets in terms of transparency and data availability, as these reports only monitor very small fragments of the market.On this account the paper aims at developing a hedonic rental price index for commercial properties using supply data for the case of Berlin. The index will be divided in 2 subcategories for office and retail. The data was provided by “Immobilien Scout 24”, a German internet platform. To find a suitable method for constructing an index, the time dummy method is compared to the hedonic imputation method. Our approach focuses on geospatial variables to improve the hedonic functions.