Insufficient drug safety is one of the major reasons for failure of drug candidates in Phase II and Phase III clinical trials. Determining toxicity early during the drug discovery process can help lower the attrition rate in clinical trials and lead to significant cost savings. In silico approaches can help to prioritize large numbers of compounds quickly and cost effectively in the early phase of drug discovery. One form of toxicity is genotoxicity due to mutagenicity. In this paper different in silico approaches for predicting mutagenicity, in particular in primary aromatic amines, are reviewed.