Ochratoxin A (OTA) is toxic fungal secondary metabolite produced by some filamentousrnfungi belonging to the genus Aspergillus and Penicillium. This mycotoxin is commonlyrnfound in coffee and cereal grains and total removal of the toxin by various food processingrnmethods is not possible. The aim of this research is to study ochratoxin A and toxigenicrnfungi in coffee and cereal grains. This dissertation contains five major chapters in whichrnbackground information, the rationale for the study and research objectives are presented inrnthe first chapter. The second chapter is dedicated to reviewing the available literature on thernproperties of OTA, the producing fungi, occurrence of OTA in foods, biosynthesis of OTA,rnanalytical methods, toxicity in human and animals, mechanisms of action and preventionrnstrategy. This section also addresses production and processing of coffee and some selectedrncereal grains. The remaining three chapters are the main experimental part of this study. Thernthird chapter focuses on the occurrence of toxigenic fungi and OTA in Ethiopian coffee forrnlocal consumption. In this chapter, fungal incidences in coffee samples and OTArncontamination levels in coffee were evaluated using various mycological techniques andrnELISA method for toxin analysis. The identities of fungal isolates were revealed usingrnspecies-specific primers and DNA sequencing techniques. The result indicated that totalrnfungal incidence mounted up to 87%. The predominant fungal genera were Aspergillus (79rn%), Fusarium (8 %) and Penicillium (5 %). Ochratosin A producing species of A.rnwesterdijkiae, A. ochraceus, A. melleus, and A. steynii were identified for the first time usingrnmolecular techniques from locally sold coffee in Ethiopia. A. westerdijkiae and A. ochraceusrnwere found to be the predominant OTA producers. The median OTA level in the locally soldrnEthiopian coffee was 1.53 Î¼ g/kg. Although samples from wet processing resulted in low median levels of OTA, they were not significantly different from other processing types (p