Perbankan syariah merupakan lembaga keuangan yang beroperasi berdasarkan prinsip-prinsip syariah Islam. Penerapan sistem ekonomi Islam dalam lembaga keuangan diyakini merupakan alternatif yang memiliki keunggulan baik bagi nasabah, bank dan perekonomian nasional. Namun keunggulan tersebut baru akan terasa manfaatnya apabila industri perbankan syariah cukup besar, yang ditandai dengan besarnya proporsi aset bank syariah dibandingkan dengan keeluruhan aset industri perbankan nasional.Hingga September 2007, aset perbankan syariah baru mencapai 1,72% dari keseluruhan aset perbankan nasional. Bank Indonesia sebagai bank sentral menargetkan aset perbankan syariah pada akhir 2008 akan mencapai 5% dari keseluruhan aset perbankan nasional. Dalam rangka meningkatkan proporsi aset tersebut, dilakukan penelitian untuk mendapatkan variabel-variabel yang berpengaruh terhadap peningkatan proporsi aset perbankan syariah tersebut. Variabel-variabel yang diteliti adalah jumlah kantor bank syariah, jumlah bank syariah yang beroperasi, porsi deposito dari keseluruhan dana pihak ketiga bank, porsi pembiayaan bagi hasil, FDR bank syariah, NPF bank syariah, kebijakan office chaneling, tingkat inflasi, SBI, SWBI, tingkat suku bunga deposito bank konvensional dan tingkat suku bunga kredit bank umum konvensional.Dari hasil analisis statistik, diperoleh variabel yang signifikan mempengaruhi proporsi aset bank syariah terhadap aset bank umum nasional adalah jumlah bank syariah, NPF bank syariah, FDR bank syariah, porsi pembiayaan bagi hasil, dan tingkat suku bunga kredit bank umum konfensional.

---

Sharia bank is a financial institution that provides banking services that complies to the rules of Islamic sharia. The application of Islamic principles in financial institution is believed to be an alternative that will benefit for customer, bank, and the whole national economic system. In the real-world facts, the benefit of Islamic financial institution will be significant only if the size of sharia banking industry is significant compared to the size of whole banking system, which is marked by the proportion of its asset against total asset of the banking system.Up to September 2007, the asset proportion of sharia banks in Indonesia only reached 1.72% of total national banking asset. Bank Indonesia, the central bank of Indonesia, targeted that sharia banking?s asset proportion shall be 5% of total national banking asset at the end of 2008. To achieve this asset proportion target, this research was conducted to obtain factors that affect asset proportion of sharia banking. The examined factors were the number of sharia bank? offices / outlets, the number of operating sharia banks, the amount-of-deposit-account proportion to the total third party fund, profit-sharing finance proportion, FDR (finance to deposit ratio), NPF (non-performing finance), the office channeling policy, inflation rate, central bank rate (SBI), the return rate of wadhiah of central bank (SWBI), the rate of deposit account in non-sharia banks and the credit rate of non-sharia banks.From the statistical analysis, it is concluded that the most significant factors that affect the proportion of sharia banking assets of total national banking assets are the number of sharia banks, NPF, office channeling policy, inflation rate, and the credit rate of non-sharia banks.