This paper examines the role of development banks in the fixed investment formation and economic growth of the country with emphasis on the facilities granted by development banks. To do this, quarterly data of the country's development banks in the period 2006-2020 and experimental tests related to the causal relationship of variables and estimating the long-run relationship between variables were used with the Granger causality test and vector autoregression method (var). The results show that the development sector facilities and total banking network facilities (except for development sector facilities) have had positive and significant effects on fixed investment formation and other banking network payment facilities except the development sector and liquidity volume have had no significant effcets. Regarding the relationship between the liquidity and total paid facilities of the banking system, with the variable of fixed investment formation, the results show that all paid facilities have had positive and significant effects and liquidity has insignificant effects on fixed investment formation. According to the results of the long-run relationship, the development sector facilities and the volume of liquidity, in the long run, have had a significant relationship with fixed investment formaton in the Iranian economy. According to the results of the short-run relationship, development sector facilities have had positive and significant impacts on fixed investment formation and investment in the economy. Therefore, it can be concluded that the development sector facilities in both the short-term and long-term have been able to have a positive and significant effect on fixed investment formation
