1. Introduction Rural bank or Bank Perkreditan Rakyat is a bank that has a specific business activity in serving mutual loans and saving for rural areas and micro small medium enterprises (MSME). The term of BPR referring to rural bank is used in this paper. Undang-undang no 10 1998 defined rural bank, opposed to general banks, as a bank that has business activities without offering services in payment transactions which follows either conventional way or syariah principles. It means that a rural bank must only focuses on mutual loan and saving activities. Bank Indonesia has a regulation that operational areas of a BPR are limited to a certain province (Bank Indonesia 2011). Bank Indonesia, on its website, informs that in April 2012 there are 1,667 conventional BPR which have in total more than 12 millions customers (or accounts) and about a quarter of these accounts are mutual loan account and the rests are saving accounts. In Bali Province alone, there are 137 active BPR. As a rural bank, BPR is ideally owned by local entrepreneurs because BPR's main purpose is to develop local economy. It is important that a BPR maintains its operations as a healthy bank to ensure its sustainability to support local businesses and economy. A well performed and healthy BPR should have the following indicators (Bank Indonesia, 2011): 1. CAR (Capital Adequacy Ratio) > 8% 2. Productivity - Non Performing Loans (NPL) < 5% 3. ROA (Return on Asset) > 1,3% 4. Cash Ratio > 4% 5. LDR (Loan to Deposit Ratio) 80% - 95% Non performing loan (NPL) indicator becomes a crucial indicator for a BPR. A BPR have no make sure that it gives loans to verified and accountable lenders so that the bank would not risk having high NPL rate. To ensure the bank gives loans to right persons, credit assessment is a critical decision making process. This paper aims to evaluate the decision tree that a BPR had made and to identify what criteria should be considered first. A new decision tree model is recommended using data mining approach. A case study is used in a BPR in Bali (PT BPR X). This bank has served their customers with various products, such as saving, time deposit, western union service, and mutual loans. This bank has a NPL indicator of 11,99% that was way above the determined range. As a result, the study is focused to reduce this NPL indicator.