The launch of nationwide Mobile Number Portability (MNP) in October 2005 has taken the Taiwan mobile telecommunication industry one step forward . The implementation of MNP has given another challenge for the mobile service providers to maintain their loyalty of existing customer as customers are allowed to retain their existing telephone number when switching from one mobile service provider to another. Under such circumstances, the pursuit of customer loyalty appears to be an essential goal of the companies' sustainable competitive advantage and growth. In response to the challenges, mobile service providers are aggressively launching various innovative and attractive marketing campaigns and promotions with the aim to retain customer loyalty. The objectives to carry out this research are to investigate the relationship between service quality and customer satisfaction and to investigate the relationship between customer satisfaction and customer loyalty in the Taiwan mobile telecommunication market. This study adopts five dimensions of SERVQUAL instrument to measure service quality in the mobile telecommunication industry, such as tangibles, reliability, responsiveness, assurance and empathy. A series of Questionnaire provide and distribute to explore the mobile service providers’ customer. The five-point Likert scale that ranged from 1=strongly disagree to 5= strongly agree. Hypotheses testing are needed to obtain the objective of this research by using Regression analysis. Result shows that the dimensions of service quality such as tangibles, responsiveness, assurance and empathy have significant effect to customer satisfaction. Furthermore, customer satisfaction was found to have significant positive effect on customer loyalty in the Taiwan mobile telecommunication industr