A WEDM ignition delay time monitoring system which can display the distribution of the ignition delay time on a real-time basis is developed in this research. The discharge pulse trains of the gap voltage and the gap current in WEDM process are rectified into square waveforms respectively before they are sent into the 89C52 microcontroller, the major component of the system, for data processing. Based on length of the delay time, the discharge pulse is categorized into two groups – the normal discharges and the abnormal discharges. After every 1000 discharges, the distribution of the ignition delay time, the percentages of the normal discharges and abnormal discharges, and the time consumed for 1000 discharges just recorded are displayed instantly on the LCD panel of the system. The normal discharges can be further divided into two sub-groups according to the specific reference ignition delay-time value set by the user. The respective percentages of the two sub-groups are also presented on the LCD panel. To verify the system, the distribution tendency of the delay time is observed under various machining conditions. It shows that the distribution is skew more to the left when the feed rate is increased or before the WEDM machine shut down itself due to frequent occurrence of short circuit discharges. On the other hand, the distribution is skew less to the left when the servo voltage is increased or when the wire breaking is about to take place. Both the tendencies are reasonable and explainable by the physical mechanism of WEDM.