Tesis ini bertujuan untuk menghitung perkiraan potensi penerimaan Pajak Penghasilan Pasal 21 tahun 2005 s/d 2008 serta membandingkannya dengan realisasi penerimaan. Hasil pengolahan data adalah perkiraan potensi lebih besar dari realisasinya. Besarnya rasio cakupan rata-rata 85 %. Sektor usaha yang mempunyai potensi terbesar serta rasio cakupan terkecil adalah industri lainnya dan jasa-jasa. Pada sektor tersebut prosentase tenaga kerja di kegiatan informal lebih besar daripada formal. Saran kepada DJP agar dilakukan perbaikan sistem informasi Wajib Pajak, pembuatan aturan pelaksanaan pemberian data dari pihak ketiga serta mengadakan pembinaan bendaharawan pemerintah.

---

This research has two main objectives. First objective is to calculate Tax Art 21 potential revenue in 2005-2008 and second objective is to compare with its actual receipts. Data tabulation shows that tax potential is greater than tax revenue. Tax coverage ratio is about 85%. Business sector which has the largest potential revenue and the lowest coverage ratio is other industry and Services industry. The percentage of formal labor is greater than informal labor in that sector. Finally, there are some suggestions for tax authority (Directorate General of Tax) to raise the tax revenues which are improving taxpayer Information system, making rule of implementing database from the third party and managing government treasurer about withholding tax duty.