Mushrooms and mushroom spores can colonize and penetrate into the matrix of agricultural products, and can produce mycotoxins in pre-harvest and post-harvest applications, processing and storage stages. Mycotoxin producing fungi in the field of agriculture; saprophytic fungi colonizing plant crops in the field and / or harvested plant products and phytopathogenic organisms infecting the plants living in the field. While it is known that only a small number of pathogenic fungi produce mycotoxins in plants, most of the spoilage fungi secrete a series of toxic metabolites. Aspergillus, Fusarium, Alternaria penicillium are the most important fungi that produce mycotoxin in food products. Mycotoxin contamination in foodstuffs is an important health threat that causes economic losses for humans and animals both in developed and developing countries around the world. Contaminated food or feed consumption with mycotoxin; resulting in acute or chronic problems such 1st International Health Sciences and Life Congress 02-05 May 2018 Burdur/TURKEY chemical or enzymatic processes prior to chemical analysis. Nowadays, it is impossible to assess the risk of masked mycotoxins in the eyes due to lack of data. For this reason, there is a need for more toxicological studies, preferably comparing the origin with masked mycotoxin. The purpose of this review is to summarize the current knowledge of the identification, formation, toxicity and effect of masked mycotoxins. Keywords: Mycotoxin, fungus, toxin, health as carcinogen, immunosuppressive or estrogenic effects. Mycotoxins; liver, kidney, nervous system and immune system. Common symptoms seen in humans are diarrhea, vomiting and gastrointestinal problems. Mycotoxin derivatives that can not be detected by traditional analytical techniques are defined as masked mycotoxins because their structure changes in plants. The chemical transformations that make up the masked mycotoxins are commonly catalyzed by enzymes and plant enzymes involved in detoxification processes. The group of masked mycotoxins includes both extracellular (conjugated) and nonextractable (bound) variants. When analytical standards are available, the structures of conjugated mycotoxins are known and can be determined. However, linked mycotoxins can not be accessed directly and it is necessary to separate them by chemical or enzymatic processes prior to chemical analysis. Nowadays, it is impossible to assess the risk of masked mycotoxins in the eyes due to lack of data. For this reason, there is a need for more toxicological studies, preferably comparing the origin with masked mycotoxin. The purpose of this review is to summarize the current knowledge of the identification, formation, toxicity and effect of masked mycotoxins.