Abstract. The purpose of this study is to identify the behavior of customers in the online environment. We analyzed the evolution, characteristics, advantages and disadvantages of this type of commerce, and its implications on the consumers. In order to identify the customers' behavior online, we selected three variables which are characterized by time intervals of the latest online order, and six variables which analyze the main problems faced by consumers of goods/services bought online (a long shipping time, damaged products, non-compliant products, fraud related issues, underperforming complaint system, technical issues, lack of customer and legal aspects). Online commerce is less developed in the Czech Republic,