Two experiments with factorial designs were conducted to study the interaction between dietary biotin and linoleate in male broiler chicks. Chicks were fed a purified basal diet containing varying levels of d-biotin (0, 200, or 400 micrograms/kg diet) and linoleate. In Experiment 1, chicks were fed the basal diet containing three levels of added linoleate (.5, 3.1, or 4.1% of diet) for each biotin level and in Experiment 2, four levels of linoleate were fed (.27, .98, 2.00, or 2.20% of diet). The average body weights of chicks fed biotin at 200 micrograms/kg of diet and .27 or .5% added linoleate were not different (P greater than .05) from those of chicks fed higher levels of biotin or linoleate supplements to the basal diets. Linoleate deficiency resulted in elevated omega-9 fatty acids (18:1 omega 9 and 20:3 omega 9) in liver and heart phospholipids. For liver phospholipids, linoleate deficiency led to reduced 18:2 omega 6, 20:3 omega 6, and 20:4 omega 6 but for heart phospholipids only 20:4 omega 6 was lowered. Biotin deficiency resulted in elevated 18:3 omega 6 in liver and heart lipids and decreased 20:3 omega 6 in liver phospholipids. Liver microsomes from biotin-deficient chicks contained increased 18:2 omega 6 and reduced 20:3 omega 6 compared with those of biotin-adequate chicks.