This paper investigates the convergence of GDP per capita across Mongolia’s twenty-two aimags and five regions***. According to international and domestic surveys, one third of the Mongolian population is living under the poverty line. Specifically, poverty is deeper in rural areas than in urban areas. Thus, one main objective of economic growth should be reducing the cross-regional income differences and maintaining real long-run per capita income growth. However, in Mongolia there is almost no research on regional economic development and regional income disparities. This is the first time that the speed of convergence to the steady state has been estimated, using a Mongolian cross-regional data set (1989-2004). The results show that there is convergence across all Mongolian aimags and regions. The speed of convergence towards the steady state position is 3 percent in the Solow model and 4.3 percent in the Ramsey model. That is substantially higher than other convergence studies. The study also finds that migration has played an important role in the evolution of regional disparities.