This study applied the service quality conceptual model and influential factors extended model proposed by Parasuraman, Zeithaml and Berry to explore the customers' perceived service quality of the telecom call centers. Besides, the perceptions of the service quality gaps and their influential factors of managers and employees were also explored. We took the Taiwan Business Group of Chunghwa Telecom as an empirical case. The results showed that there existed some significant differences between the customers' perceived service and their expected service. And the service delivered by employees did not match the standards designed by managers. On the other hand, the teamwork, role ambiguity, and role conflict had the most significant influenced on the service gaps. Finally, we proposed some managerial implications and suggestions for the future researches.