This paper presents an empirical investigation to study the effect of five factors on purchasing food product including brand and reputation, being green product producer, quality of packaging, taste of food products and materials used in products. The study designs a questionnaire consists of 20 questions, distributes 440 questionnaires among some consumers who were regular customers of food chains in west part of city of Tehran, Iran and managed to collect 225 properly filled ones. The study uses binomial test to verify five hypothesis of the survey and it has confirmed the effects of four variables including brand and reputation, quality of packaging, taste of food products and materials used in products. In our survey, there are some positive and meaningful correlations among different pairs of five variables of the survey where the highest correlation is between materials used in products and quality of packaging (r=0.606, Sig. = 0.000) and between Quality of packaging and being green product producer (r=0.545, Sig. =0.000).