P PT. Indonesian Tooling Technology (ITT) is a company engaged in manufacturing.The company uses Enterprise Resource Planning (ERP) system that enables thecompany to integrate all parts or field in the manufacturing process. Based on thepreliminary study, it was found that the system in the production module often donerepair and development while the user of the system is still having difficulties or hardtime in adjusting nor learning the system. This study is conducted for the purpose ofthe user in terms of ERP User Interface System and assisted the establishmentrequired. The method used to study the usability of the sistem is using the method ofUsability Testing with Performance Measurement technique that is used to processthe quantitative data in this research and Thinking-Aloud Protocol technique is usedto process the qualitative data from the research’s respondents. Stages of thisresearch will begin by determining the tasks of analysis to be conducted in this studyand determine the group of respondents of this research. The result of this research isthe finding of usability problem with highest rate in task 1 that has been conductedthrough out this research which is SPK Query based on the result from PerformanceMeasurement technique and is combine with the data of verbal results fromrespondents in Thinking-Aloud Protocol technique that states the biggest problemslies on the Interface of the system.