We report on electrically driven amplified spontaneous emission and Lasing in tetracene single crystals using field-effect electrodes for efficient electron and hole injection. For Laser action, feedback is provided by reflections at the cleaved edges of the crystal resulting in a Fabry-Perot resonator. Increasing the injected current density above a certain threshold value results in the decreasing of the spectral width of the emission from 120 millielectron volts to Less than 1 millielectron volt because of gain narrowing and eventually Laser action. High electron and hole mobilities as well as balanced charge carrier injection Lead to improved exciton generation in these gate-controlled devices. Moreover, the effect of charge-induced absorption is substantially reduced in high-quality single crystals compared with amorphous organic materials.