Laser action in lithium neodymium tetraphosphate, LiNdP4O12(LNP), crystals, pumped with AlxGa1-xAs electroluminescent diodes, is reported, citing both end- and side-pump configurations. The threshold incident light-emitting diode (LED) intensities at about -30°C are 14.9 W/cm2and 7.2 W/cm2for end and side pump, respectively. Temperature dependences of threshold, stimulated emission cross section, and round-trip loss were measured experimentally. Possibility of room-temperature CW operation, maximum output power, and optimum coupling are discussed. Taking account of improvements of pumping optics, crystal homogeneity and LED structure, LED intensities required for room-temperature CW operation are 35 W/cm2and 8.5 W/cm2for end and side pump, respectively.