ln order to evaluate production and economic benefit of lettuce (Lactuca sativa L.), four doses of an organic fertilizer, three of the mineral fertilizer 25-4-24-2-1 and a check, an experiment was carried out at the Cajica municipality (Cundinamarca), on a Typic Hapludalfs soil of medium fertility level and 2600mosl. A complete randomized blocks design with factorial arrangement 4 x 5 for 20 treatments and three replications of 12m2 with four rows of ten meters length and 30cm between them, was tested. Salinas variety Batavia type was used. The effective area was 80.000 plants/ha. The ieveis used were 0-200-400-600kg/ha of mineral fertilizer, and 0- 1500-3000-4500-6000kg/ha of organic fertilizer. After 30 days of germination the plants were transplanted and with an interval of eight days, five samples were taken to obtain the fresh weigh per plant in order to know the harvest time. The results indicated that 70 days after germination is an appropriate period for harvest. In total yields mineral fertilizer and its combination with organic fertilizer was better than organic fertilizer alone. The most favorable benefit cost analysis was 4.3 with 600kg/ha of mineral fertilizer mixed with 1.500kg/ha of organic fertilizer. With 600kg/ha of mineral fertilizer mixed with the organic fertilizer, and with 400kg/ha of mineral fertilizer mixed with 3000 and 6000kg/ha of organic fertilizer the best yield and price per plant was obtained.