This study focused on analyzing the influence of ADSL service quality (reality, responsiveness, assurance, empathy and tangibles) on customer satisfaction at Dong Hy Telecommunication Center, Thai Nguyen Telecommunication Corporation. 380 customers who currently using the service of the Center was selected for this study. The research findings showed that 4 of the 5 factors of service quality (responsiveness, assurance, empathy and tangibles) were found to have a positive influence on customer satisfaction. Based on these findings, this study proposed some recommendations to increase, service quality and customer satisfaction at Dong Hy Telecommunication Center, Thai Nguyen ,Telecommunication Corporation.