During the production of crude oil a lot of problems may occur. One circumstance which significantly affects the petroleum industry worldwide, especially in low temperature environments, is paraffin precipitation. In consideration of this fact, oil producing companies lose millions of dollars every year. The first part of this work deals with the theoretical background, which consists of the following: causes of paraffin deposition, problems related to paraffin deposits, and methods for removing and avoiding paraffin deposition respectively. The second part of this work is based on laboratory work conducted to find a suitable sample preparation method and to reproducible investigate and measure the paraffin building behaviour of crude oils treated with different types of chemical inhibitors on a rheometer. The final aim of this work was an inhibitor screening of 19 chemical inhibitors of different types and manufacturers. 13 different OMV crude oil samples produced from wells situated in the lower part of Austria were taken to test the inhibitors. Thus, it was possible to identify the 5 most efficient products.