Indiane-commerce market is expected to reach $100-billion mark by the end of 2020, triggered by increasing internet usage, discounting and investment by online retailers. Promotion the 4th ‘P’ of marketing is playing a major role. Promotion refers to the entire set of activities, which communicate the product, brand or service to the user. The idea is to make people aware, attract and induce to buy the product in preference over others. Flash sales, sometimes also called as deal of the day are a part of sales promotion which provides its customer with a special deal or discounts on selective products for a limited time .It is helping companies to lure its customers to visit their web sites again and again. The study focuses on the role of online sales promotion done through flash sales in attracting customers and generating sales for web sites. The study is based on the previous researches, newspaper articles, magazines and journals. This Study indicates that flash sales have helped companies to attract masses but they were not able to capitalize on the traffic generated