Abstrak : Penelitian ini bertujuan untuk mengetahui dan menganalisis pencapaian tujuan desentralisasi dan dampak Pembentukan DOB Kabupaten Mamasa. Penelitian ini menggunakan pendekatan deduktif dengan paradigma kualitatif dan jenis penelitian studi kasus dengan tingkat analisis deskriptif-komparatif-explanatory. Data dikumpulkan melalui dokumentasi (telaah dokumen). Teknik analisis data terdiri atas tiga kegiatan pokok, yaitu: reduksi data, penyajian data dan penarikan kesimpulan dan verifikasi. Hasil penelitian menunjukkan bahwa berdasarkan: perbandingan kesejahteraan rakyat yang terdiri atas: perekonomian daerah (pertumbuhan PDRB non-migas, PDRB per Kapita, dan angka kemiskinan) lebih baik Kabupaten Mamasa, sedangkan rasio PDRB Kab. Terhadap PDRB Provinsi lebih baik Kabupaten Polman. Keuangan Pemerintah Daerah (ketergantungan fiskal, kapasitas penciptaan pendapatan (PAD), dan kontribusi sektor pemerintah lebih baik Kabupaten Polman, sedangkan proporsi belanja modal lebih baik Kabupaten Mamasa. IPM (lama hidup (AHH), tingkat pengetahuan (AMH) dan (RLS), dan standar hidup layak) lebih baik Kabupaten Mamasa. Berdasarkan perbandingan kualitas pelayanan publik yang terdiri atas: pendidikan, kesehatan dan infrastruktur jalan (rasio siswa per sekolah (SD+SLTP dan SLTA), rasio siswa per guru, ketersediaan fasilitas kesehatan, ketersediaan tenaga kesehatan lebih baik Kabupaten Mamasa, sedangkan kualitas infrastruktur jalan lebih baik Kabupaten Polman. Kinerja aparatur pemerintah daerah (rasio pegawai terhadap penduduk dan persentase aparatur pendidik lebih baik Kabupaten Mamasa, sedangkan kualitas pendidikan aparatur (S1) dan persentase aparatur paramedis lebih baik Kabupaten Polman. Kata kunci : Dampak Pembentukan Kabupaten Mamasa, Kesejahteraan Rakyat, Pelayanan PublikAbstract : This study aims to identify and analyze the achievement of decentralization in terms of the establishment of Mamasa Regency as a new autonomy area (DOB). This research is a case study and employs deductive approach with qualitative paradigm with descriptive-comparative analysis of the level-explanatory. Data were collected through documentation (document analysis). Data analysis technique consists of three main activities, namely: data reduction, data presentation and conclusion and verification. The results showed that Mamasa Regency has a good performance in terms of comparison of welfare of the people which determined by the regional economy development (non-oil GDP growth, GDP per capita, and number of poverty). In addition, Polman Regency has better achievement in terms of ratio between districtsâ GDP and provincialâs GDP. Moreover, regarding public budgeting which determined by fiscal dependency, income generation capacity (PAD), and the contribution of the government sector, Polman Regency has a good performance compare to Mamasa Regency. However, Mamasa Regency has a better proportion of capital spending compare to Polman Regency. Additionally, Mamasa Regency has a higher level of the Human Development Index (HPI)âdetermined by life expectancy, literacy rate, and decent living standards. Lastly, this study analyzes the comparison of the quality of public services which focusing on education, health and road infrastructure sectors between Mamasa Regency and Polman Regency. Education services are examined by ratio of students per school (elementary school, junior and senior), ratio of students per teacher. Health services are explored by the availability of health facilities, availability of health workers. The study found that Mamasa Regency has good performance in education and health services and performance of local government officials (the ratio of employees to the population and the percentage of educatorâs better apparatus. However, Polman Regency has a better quality road infrastructure, the quality of education apparatus (based on educational background with minimum bachelor level) and the percentage of paramedical personnel. Key words : Impact Formation of Mamasa, Social Welfare, Public Services