The objective of this paper is to develop an internal halal traceability system in open source ERP system that is used to ensure the 'halalness' of raw materials. The chicken meat processing company is a case study of this research to testing and validating the customized software on the open-source ERP system. In the first phase (modelling), four stages have been conducted to map the internal business process, to model the relationship actors using the use case diagram, determine the lot number code, and to determine the halal information tracing data model using the class diagram. In the second phase, two stages of research are conducted to testing the applicability of customized software and to validating with opinions for functions and design of customized software from case study's workers. Two process transactions in customized software to ensure the halalness of raw materials such as purchasing and manufacturing order transaction. Their opinions indicated that the functions and design of customized software have been fulfilled.