To be able to correctly price corporate bonds, it is essential to determine the credit spread. The credit spread is a premium, which compensates the higher risk of a corporate bond. The risks of corporate bonds determine the credit spread level and consist of interest rate risk, spread risk, liquidity risk and in particular the credit risk. This masters thesis analyzes these risks and their influence on the credit spread. Moreover the choice of the appropriate risk-free interest rate is an important aspect. The risk-free interest rate can be derived from various products on the capital market, such as government bonds and interest rate swaps. By the derivation of the risk-free interest rate, there can be a mismatch between the different capital market products. The credit risk, which divides into migration risk and default risk, has significant influence on the credit spread. To this end, the Structural Model by Merton (1974), the KMV-Model and the Reduced-Form Model by Jarrow and Turnbull (1995) as well as extensions to these models, are examined closely. By means of these models, the default risk can be valued, whereof the credit spread can be derived subsequently. With the aid of empirical studies, it is examined how well these models can reproduce Credit Spreads observed on the market. In the existence of discrepancies from model results to market data, potential reasons relating thereto are examined.