A washing machine that performs refresh washing in which smell or mold that permeates laundry can be removed, and a method of controlling the washing machine. When clothes that are kept for a long time without being worn or laundries that are hardly contaminated due to a short wearing time are washed, a refresh washing course in which various smell or mold that permeates laundry can be removed using a very small amount of detergent, is performed. Thus, overuse of detergent caused by an excessive use of detergent can be prevented, and since the necessity for rinsing is low due to the use of the very small amount of detergent, an intermediate dehydration operation may be omitted, or an intermediate dehydration revolutions per minute (rpm) may be reduced so that washing and rinsing operations do not need to be excessively performed and thus damage of laundry is reduced.