In the present day mobile telephony business that is characterized by cut-throat competition from different players, the concept of customer satisfaction has become a critical success factor that is expected to lead to stronger competitive position and consequently to a larger market share and profitability. The research aimed to establish the factors affecting the level of customer satisfaction of Safaricom Customers in Nairobi, Kenya. Using the descriptive research design, the study sought to establish the factors affecting customer satisfaction at Safaricom (K) Limited. The constructs that defined the level of customer satisfaction in the study were the product features, product differentiation, and perception of fairness in the prices charged on the firm products as well as customer service. The data was collected from the Safaricom customers visiting the three Safaricom shops in Nairobi CBD. The study used descriptive research design and the questionnaire was the main instrument of data collection. The study established that the firm’s product features, capacity to differentiate its products, perception on the fairness of the firm’s product pricing and also customer service practices affect the level of customer satisfaction within customers visiting Safaricom Outlets within the Central Business District. The study findings were that the capacity of Safaricom to differentiate its product offering from the other competitors acts as a source of competitiveness to the firm due to the product being able to meet a particular need of the customers. The study found that Safaricom should enhance its rewards scheme to its customers since the strategy was found to increase customers’ level of satisfaction. Further, the study found that the level of customer service at Safaricom influences customer satisfaction and it was recommended that more customer agents and support points be opened outside the CBD. The limitation of the study included the sample selection procedure in which the narrow and specific focus of the scope means that the results are limited to Safaricom Ltd may not translate to other industry and national contexts. For the recommendation, the study set that the firm enhances the features of its product to have a seamless interface with different financial institutions without compromising the security of the customers’ deposits.