This paper is aimed to examine the hypothesis that regional disparities tend to persist because there ae differences of implementing regional policy in economic development. This issues has become a crucial topic in economic regional analysis both before decentralization implementation and after. This study investigated the determinant factors of profincial convergence after 20 years (since 1985 - 2006). Using a- conditional convergence analysis based on panel data we found that speed of income per capita convergence by 2 6 percent with half- time to reached steady state condition by 26 years. In this period share of investment that respresented by domestic fixed capital information share of agriculture sector and manufacture industry have important role to converging interprovincial income percapita in Indonesia. Comparing of convergence for before (1985 - 2000) and post decentralization (2001-2006) get the speed of convergence by 3 30 percent and 1 06 percent respectively. They are different dterminants of source of income percapita growth for those persiods.