Fluorescence microscopy has employed mercury arc lamps for decades because of their high power and broad spectrum. Fluorophores and filter sets have been developed around the peaks of the spectrum offered by these lamps. When LEDs first entered the fluorescence microscopy arena, prices were high and output was low, but in recent years there have been significant advancements in LED capabilities for microscopy. This article aims to educate users of fluorescence microscopy about the benefits of LEDs compared to conventional mercury arc lamps.