The main purpose of the present research is to study the effective factors on increasing visits of international tourists to a recognized cultural or natural heritage in the UNESCO World Heritage List. The method of this research is a quantitative approach using the attributive technique. Data gathering was done based on information and statistics recorded by statistical centers and organizations in Iran including Cultural Heritage, Handicrafts and Tourism Organization, Iran Travel and Tourism Organization …. After gathering information, research data was analyzed by Eviews7 software. The main hypothesis of the research was conformed and the value of statistic t for the research variables, (i.e. recognition of the heritage in UNESCO List, improving services, the geographical distance of the countries, changes of the exchange rate on the part of the visiting country, social security, economic development of the visiting country, the number of attractions in Zanjan, and the population of the tourist country), showed that except for social security, distance and exchange fluctuations, all of them are placed in the realm of rejecting the null hypothesis. It means that all variables are significant in the model. The determination coefficient equals 0.77, which means that 77 percent of the changes of the dependent variable were explained by independent variables. This would be a significant percentage.@en