Mycotoxins are secondary metabolites produced by molds growing on grain, feed, or food in the field or in storage. Some of these compounds may be seriously detrimental to human health. Mycotoxins of concern are: aflatoxin, vomitoxin, zearalenone, and fumonisin. Early detection of mycotoxins or the fungi producing them is crucial for preventing supply of contaminated food material including wheat grain. This study was undertaken to develop rapid, reliable and reproducible procedures for screening the wheat grain supplies being imported into Saudi Arabia. Pure cultures of mold species were isolated from the grain samples collected from discrete regions of Saudi Arabia. Enzymatic and antibacterial activity of the isolates was assayed to develop marker systems for detecting the molds in a sample. Major mycotoxins were detected and quantified with HPLC (high performance liquid chromatography) procedures. Mycotoxegenic mold species were identified by PCR (polymerase chain reaction) procedures using primers specific for ITS (internal transcribed spacers) and microsatellite sequences of the rDNA. The study showed that presence of mycotoxins or the molds producing them may be detected at an early stage in wheat grain samples with the help of molecular procedures.