A method of controlling uplink access in a wireless communication system is provided. The method includes: generating an access probability sequence consisting of an access probability determined with respect to a radio resource used for data transmission; transmitting data according to the access probability included in the access probability sequence; receiving a success/failure result on the data transmission; and regulating the access probability used in the data transmission according to the success/failure result. Accordingly, each user equipment performs a simple control process for attempting random uplink access according to an access probability sequence and for changing the access probability sequence according to success/failure of uplink data transmission, thereby decreasing a probability of collision between user equipments, thereby increasing data transmission efficiency in a system employing a plurality of user equipments.