Cyclone Nargis made landfall in Myanmar on 2 May 2008 causing widespread destruction. With fatality estimates of about 80,000, Nargis is likely one of the deadliest named storms ever to occur. The forecasts concerning the intensification of Nargis relied on satellite imagery, which showed to be insufficient. Our study indicates that lightning activity can be an additional resource to identify intensification episodes. Previous investigations using WWLLN (World Wide Lightning Location Network; http://wwlln.net) and other lightning networks have reported an association between tropical cyclone intensity change and episodic inner core lightning activity (within 100 km of the minimum central pressure) in North Atlantic and Western North Pacific storms. However, studies using other networks had limited oceanic coverage, while WWLLN has global coverage. Moreover, analyzes of Hurricanes Katrina and Rita (2005) have shown that WWLLN data are in good agreement with data from other lightning networks and are useful for studying tropical cyclones. In the present work, we combine WWLLN, TRMM (Tropical Rainfall Measuring Mission) satellite-borne radar data, cloud-top temperatures, and pressure and wind data to investigate the inner core lightning activity during the entire lifespan of Nargis. Our results show outbursts of lightning at regions of deep convection prior to and during changes in intensity. Particularly, the main intensification episode of Nargis, which was not predicted by forecasters, was preceded by lightning that pinpointed the region of active convection in the eyewall. Our results indicate that lightning data can be used to better predict the strengthening of future North Indian Ocean tropical cyclones.