A method and apparatus are provided for reporting a buffer status to a Node B, by a User Equipment (UE), in a mobile communication system. The method includes checking if a resource for data to be transmitted to the Node B is available, when there is a buffer status report triggered to be transmitted to the Node B; transmitting the buffer status report using the available resource, if the resource is available; and transmitting a scheduling request to the Node B, if the resource has not been allocated for a predetermined time duration.