Background and aims: Synthetic colors (dyes) are used widely in food as one of food additives. Inappropriate use of dyes creates hazards such as allergy and cancer for consumer. This study was performed with aim determine the prevalence contamination foods to synthetic colors. Method: this investigation is a descriptive study. In this study were tested the number 2458 food samples such as candy (Nabat), poolaky, charkhandi, cream and none cream sweets, ice-cream, barbecue chicken and saffron fluids. These samples were collected randomly by the sanitary inspectors from factories, small manufactures, confectionaries, restaurants and fast-foods during 2010-2013 and in order to control and supervision were sent to food and beverage control laboratory of Shahrekourd University of medical sciences. All samples were examined according to national standard number 2624 with thin layer chromatography (TLC) method. Results: this study showed that 33.8% samples (range 7.1-56.2%) were colored with dyes. Tartrazin formed 67.8 % of synthetic colors used. The most common dyes were observed in charkhandi samples with 56.2% and the lowest rate in ice-cream with 7.1%. Conclusion: this study demonstrated that the use irregular synthetic colors in food have been widespread and continues this situation threat health of society. Therefore, training and supervision is essential for maintaining healthy communities.