ABSTRACT The objective of this study was to evaluate the effect of three levels of crude cottonseed oil on performance, organ weights, and blood parameters of growing broilers. Carcass and cut yields after 33 and 42 days of age and the economic viability of the diets were also evaluated. Male broilers of the Ross line were distributed in a completely randomized design, in a 4 × 2 factorial arrangement (0, 2, 4, and 6% inclusion of cottonseed oil, with and without ferrous sulfate) with five replicates. In the period from 22 to 33 days, quadratic and increasing linear effects were observed on feed intake and weight gain, respectively. Feed conversion during the same period was better with the addition of ferrous sulfate. The addition of ferrous sulfate caused a reduction in heart weight. From 22 to 42 days, carcass and cuts yield, organ weight, and intestine length were not influenced by the levels of oil or by the addition of ferrous sulfate. Supplementation with iron salts provided a lower red blood cell count and increased mean cell volume. Balanced diets formulated with up to 6% of crude cottonseed oil for broilers from 22-33 and 22-42 days of age do not affect their performance or the weight of their organs. Supplementation with ferrous sulfate improved feed conversion up to 33 days. Diets formulated with 4% cottonseed oil supplemented with ferrous sulfate are economically viable in the period from 22 to 42 days.