A microprocessor-based electronic timekeeping apparatus or stopwatch for measuring multiple intervals of time, such as the elapsed times of a race horse covering successive distances of a race course, is disclosed. This hand-holdable, self-contained stopwatch has four multiple-digit display fields for simultaneously displaying up to four measured intervals of time preferably in minutes, seconds and fractions of a second. In a first mode of operation, the stopwatch is used to measure and display four overlapping intervals of time having a common starting time and different stopping times. In a second mode of operation, the stopwatch is used to measure multiple intervals of time which have an operator-determined untimed period between successive intervals. The stopwatch includes additional display fields for indicating the mode of operation and the specific intervals of time being displayed. It also includes internal memory so previously measured and displayed intervals of elapsed time can be stored and displayed later. Preferred methods of operating the stopwatch are also disclosed.