Ochratoxin A (OA), zearalenone (ZON), moniliformin (MON) as well as trichotecenes and fumonisines (FUM) are naturally occurring contaminants of cereals and animal feed. They pose a health risk not only to humans but also to livestock and, as a consequence, may cause economical losses either due to unfavorable effects on domestic animals themselves or to an increased potential for health effects in human beings consuming mycotoxin-contaminated edible animal products. At present, large-scale studies are carried out in EU countries to determine a safe, admissible concentration of these toxins in cereals and their processed products. The aim of this review is to collect and summarize information concerning the properties, occurrence and toxicity of these mycotoxins.