In this study investigated relationship between IRAN underground economy and unemployment rate for annual data during the period 1973-2015. therefore first , estimated underground economy white using multiple indicator-multiple causes(MIMIC) and next, investigated relationship between underground economy and the unemployment rate. in this paper Furthermore, co-integration relationship between the underground economy and unemployment rate tested causality relationship between underground economy and the unemployment rate with Toda- Yamamoto approach. resulte indicated The underground economy has been rising during study priod Although shown fluctuation in the first half of the period. So that has been increased from 7% in 1973 to 36/5% in 2015. Johansson co-integration test point out the existence of a long-run relationship between the underground economy and unemployment rate and also causality test indicated unidirectionalcausation that runs from unemployment rate to underground economy.