Non-conventional leafy vegetables can be a good source of nutrients for the human diet, but there is little information on fertilization for these species. This study aimed to evaluate the effect of organic fertilization with cattle manure on the production and chemical composition of non-conventional leafy vegetables. The experiment was conducted in a greenhouse, in pots. The factors under study were non-conventional leafy species (Rumex acetosa, Stachys byzantina and Lactuca canadensis) and cattle manure doses (0; 5; 10; 15; and 20 t ha-1), arranged in a 3 x 5 factorial scheme, in a randomized block design, with four replications. At harvest, the following parameters were evaluated: stem diameter; total number of leaves; number of leaves with commercial standard; shoot fresh and dry matter; macro and micronutrients concentration and accumulated amounts in the shoot. The fertilization with cattle manure altered the stem diameter, number of leaves with commercial standard, shoot fresh and dry matter, as well as the accumulation of the nutrients N, P, K, Ca, Fe, Mn and Zn in the shoot of the three species studied. The additions obtained varied from 1.1 to 2.1 times, in relation to the treatment without organic fertilization, and the dose equivalent to 20 t ha-1 was the most adequate one. The organic fertilization with cattle manure increases the production and accumulation of nutrients in the non-conventional vegetables evaluated, with R. acetosa presenting a nutrient accumulation higher than S. byzantina and L. canadensis.