Sales promotion is a marketing technique used by marketer to encourage and influence prospective and current customer to purchase their product in certain period of time. Chatswood coffee is a coffee shop that has been established since 2015. This research uses the theories about sales promotion and customer purchasing decision. The framework of this research is to find out the impact of sales promotion towards customer purchasing behaviour. The method used by the writer in this research is quantitative method. Primary data and secondary data are used to support this research. This research uses coefficient determination test and hypothesis test to find out the impact of sales promotion towards customer purchasing behaviour. Coefficient determination test result shows that there is 36.9% impact from sales promotion towards customer purchasing behaviour. Besides, the correlation test obtains 0.608 (60,8%) which means the relationship between sales promotions andcustomer purchasing behaviour is strong and positive relationship. Recommendations of this research are, first sales promotion has a significant impact towards customer purchasing behaviour, secondly coupons are able to attract customers’ attention where company needs to maintain and improve the benefit of coupon.