Legal Writing entitled “Implementation of electronic procurement (E-Procurement) Based on the principle of effective efficiency and transparency in the district government of Kotabaru South Kalimantan province". The method used in writing is Normative Legal Research. The reference sources used are primary legal materials and secondary legal materials. Data collection techniques by conducting interview studies with sources and conducting literature studies. The research location is at UKPBJ Kotabaru Regency. Procurement of Goods and Services is the activity of Procuring Goods / Services by Ministries / Institutions / Regional Apparatus financed by the APBN / APBD whose process is from the identification of needs, up to the handover of work results. The implementation of goods and services is now carried out electronically, which is now called e-procurement. The implementation of e-procurement also implements the Principles of Effectiveness, Efficiency and Transparency. Kotabaru Regency implements an e-procurement system by implementing the Principles of Effectiveness, Efficiency and Transparency, but there are obstacles that occur, namely internal obstacles and external obstacles. The Kotabaru Regency Goods and Services Procurement Section overcomes these obstacles by providing solutions and also steps, namely in internal constraints there are efforts to improve information security in the e-procurement system, increase security from Falsification Documents, external constraints are efforts to provide training or teaching for users, especially Electronic Procurement (E-Procurement) providers, improve network security in the system and improve the internet network.