The purposes of the study are to analyse the influence of service quality whose variables consist of tangible, reliability, responsiveness, assurance, and empathy to customers satisfaction and to find out the most influence variable related to the costumers satisfaction PT. PLN (Persero) Service Unit Salatiga . The methods of collecting the data used were interviews, questionnaires and library studies. The type of the data were qualitative and quantitative. The method of analysis was used multiple linier regression methods, t-test, and F-test. The result showed that the service quality which consisted of Tangible, Reliability, Responsiveness, Assurance, and Empathy together had a positive influence. Where the regression equation Y = 0,383X1 + 0,123X2 + 0,152X3 + 0,176X4 + 0,403X5 + e . In addition, the F-test found that service quality had a significant effect on customers satisfaction with a significance level of 0,000 or 0%. However, based on partial test (t), all variables have a significant effect on customers satisfaction with a significant level for Tangible of 0,000 or 0,0%, Reliability of 0,007 or 0,7%, Responsiveness of 0,008 or 0, 8%, Assurance of 0,012 or 1,2% and Empathy of 0,000 or 0,0%. The results showed that significant level of t-count was bigger than significant of constanta.