This research work entitled Assessment of the biomass of "Lettuce" (Lactuca sativa L.) GREAT LAKES 659 variety, treaties with four doses of chicken manure from birds of stance enriched with beneficia! microorganisms in Lamas province-San Martín~ it has been developed in Lamas city during two periods, the first harvest of the February 02 to May 03 of 2014, and the second harvest of the May 10 to July 27 2014, whose objectives were apply four doses of chicken manure from birds of position in "lettuce" productíon (Lactuca satíva L.), determíne the performance of the "lettuce" bíomass (Lactuca sativa L.) treaty with the more efficient dose of chicken manure from birds of position and find the effect of chicken droppings of birds of position depending on the "lettuce" biomass (Lactuca sativa L.) influenced by the action of the beneficia) microorganisms applied. In which we have the follo...