The present res.earch took place at the experimental station of the "El Porvenir", located in 14,5 km of the Marginal Sur Road, Juan Guerra, District, Province of San Martin (Perú), located al 6º 35'south latitude, at 232 above sea level, a~d 76º 30' longitude. Our aim was to find and the best nitrogen dose and an adecuate seed planting density far hybrid corn - type PIMSE 3. The results were evaluated in three levels nitrogen fertilizing and there different seed - planting density related to harvest efficiency in the Bajo Mayo river area. The nitrogen dose was 120, 150 and 180 kg por hectare and the seed - planting density was 50 000, 62 500 and 70 ooo. plants por hectare, using nitrogen in two times: first time, 1 O days after seed planting, and the second time at the present harvest. We used the experimental design of Divided lost or Parcels of Ground divided in four areas analyzin...