Agricultural Research is one of the most important factors in agricultural development, thus, the role and importance of research is increasing. Within the past years, all developed and consequently developing countries have engaged their most attention to promote their researches indexes. This study is investigating the effect of agricultural research on the distribution of income and agricultural value added in Iran, during the period of 1976 - 2012. Three SLS methods were used to determine the income distribution functions, value added and per capita income. The results showed that agricultural researches were effective on improvement of agricultural value added. The results also express that continuance in agricultural researches can increase per capita income and less inequality of income distribution. Effect of agricultural value added on inequality of income distribution was low but though increase in agricultural value added and decrease it.