This research paper entitled "Effect of dose of magnesium oxide in the cultivation of cucumber (Cucumis sativus L.) Hybrid EM 160 F1 Hyb American Slicer, in the district of Lamas", was conducted in order to evaluate the effect of four doses of magnesium oxide in the production of culture Gherkin (Cucumis sativus L.), was used for the statistical design of randomized complete block, with three blocks and five treatments, whose variables studied were: number of inflorescence produced by plant, number of fruit per plant, fruit weight, fruit length, fruit diameter, yield frutos.Ha- 1 (kg), fruit yield in Tn.ha-1 and economic analysis. The results obtained in this investigation indicate that treatment T 4 (800 kg ha-1 of magnesium oxide) won the largest and best averages for the variables studied, because that magnesium induced physiological responses that promoted growth, plant development, ...