Twenty Sex Sal cockerels were randomly assigned to each of eight groups; each of four nutritionally balanced diets were fed to two groups from 1 d through 4 wk of age. These diets contained 0, 2, 5, or 10% stabilized flaxseed meal that provided a calculated 0, 0.45, 1.11, or 2.22% n-3 fatty acids, primarily linolenic acid. At 3 wk of age, one group of chickens from each diet treatment was infected with Eimeria tenella and was housed in separate but similar conditions to uninfected control chickens. At 6 d postinfection, chickens were weighed, bled, killed, and scored for lesions. No level of dietary flaxmeal tested provided protection against weight gain depression, increased feed conversion ratios, or lesions. We concluded that these diets did not protect against E. tenella infection because levels of linolenic acid were not high enough, and the oxidative potentials were well suppressed by vitamin E and other stabilizers present.