The purpose of this study was to examine the effect of customer service strategies on customer retention in a local commercial bank using Investrust Bank Plc. as a case- study being the only indigenous bank in Zambia. Primary data was collected from bank customers and employees using the sample size of 106 respondents. This study adopted a descriptive survey approach and data was analysed using Microsoft Excel and thematic survey. The findings revealed that 77% of the customers were generally satisfied with the bank’s service quality. Further, a total of 63% affirmatively indicated their loyalty of being retained with their bank for the next decade. In establishing how service quality correlated with customer retention, five servqual dimensions were employed namely tangibility (r=0.64), reliability (r=0.61), empathy (r=0.68), responsiveness (r=0.58) and assurance (r=0.52). All the 5 dimensions of service quality recorded a positive correlation to customer retention ranging from 0.52 to 0.68. However, tangibility, reliability and empathy posted stronger association to customer retention than responsiveness and assurance in this study. Therefore the following recommendations emerged from the study findings: 1. Investrust Bank Plc. should ensure that their service quality is improved by obtaining customer feedback to identify the gap areas as well as to stay contemporary. 2. Investrust Bank Plc. Should periodically train and reward staff especially front liners at the bank. 3. Investrust Bank Plc. should urgently address the Tangibility dimension of service quality in terms of internet banking, faulty ATM systems, delays in issuance of banking instruments like cards, cheque books etc.