Regarding this research focus on PT. Indosurya Medan that why lots of customers are attracted with the saving and loan service products that PT. Indosurya provided. Instead of that, research also focus on the marketing strategy used by PT. Indosurya that increase sales of saving and loan service products. This research is done by qualitative method by interview with Business Manager at PT. Indosurya Medan. Result of research indicates that marketing strategy implemented by PT. Indosurya Medan such as product strategy, price strategy, place strategy and promotion strategy. By implementing marketing strategy, customers will attracted with existing service products that company provided thus can keep increasing the sales of saving and loan service products. The marketing strategy must mbe maintained in order not to experience decrease the sales of saving and loan service products in the following year. The reason why company PT. Indosurya Medan implemented marketing strategy because to maximize sales of saving and loan service products.