The purposes of the research are to find out the level of customer satisfaction on the service provided at PT Masaji Tatanan Container Semarang based on five dimensions of service quality, namely Tangible, Reliability, Responsiveness, Assurance, and Empathy and to find out which aspects should be improved. The methods in collecting data are observation, literatur review, and questionnaires. The methods used to analyze the questionnaires items are validity test, reliability test, and to customer satisfaction index and diagram cartesius are used to inform the result. The population of this research is reguler customer of Masaji Tatanan Container, PT Semarang. The Samples were 55 respondents and sampling technique is purposive sampling. The variables of this research are dimensions of service namely: tangible, reliability, responsiveness, assurance, and emphaty. It is Found that Customer Satisfaction Index for dimension of tangible is 87,85% (satisfied), dimension of reliabilty is 57,59% (satisfied enough), dimension of responsiveness is 76,84% (satisfied), dimension of assurance is 89,49% (satisfied), and dimension of emphaty is 86,27% (satisfied), so the Customer Satisfaction Index belongs to the satisfying category. These results were calculated by cartesius diagram to identify company performance improvement. The calculation of the cartesius diagram to customer service, in quadrant A or top priority, many indicators should be improved.