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The objective of this study was to evaluate the use of a combination of essential oils, prebiotics and antibiotics on broiler production. The treatments consisted of a normal diet meeting the nutritional requirements, and diets with a 5% reduction of nutritional requirements, supplemented or not with antibiotics (En+Sal) (10 g ton-1 enramycin and 125 g ton-1 salinomycin) or a blend of essential oils (EOFOS) (oregano, anise and lemon) plus fructooligosaccharides (125 g ton-1). A total of 1,152 male one-day-old broilers were randomized by weight and distributed into a 2*3 factorial design, consisting of six treatments with each treatment containing eight replicates of 24 birds per experimental unit. The Student-Newman-Keuls test was performed at 5% probability. Broiler performance was evaluated at 10, 21 and 42 days, intestinal morphometry was evaluated at 21 days, microbiological cecum counts at 33 days, blood parameters at 35 days and carcass and cuts yield at 42 days of age. Broilers fed reduced diets had a reduction in performance (P < 0.05). There was an interaction (P < 0.05) between diet type and prebiotics for jejunum villus height and villus height:crypt depth ratios for all intestinal segments. There was no effect (P > 0.05) of growth promoters and diet type on the Lactobacillus and Bifidobacterium populations within the gastrointestinal tract. There were no differences for duodenum or ileum villus heights (P > 0.05). Broilers fed EOFOS showed higher villus height in the jejunum at 21 days. There were no effects on blood parameters of different diets and growth promoters (P > 0.05), nor on carcass and cuts yield, abdominal fat and relative liver weight (P > 0.05). Broilers receiving the normal diet with EOFOS showed higher villus height in the jejunum at 21 days when compared to the normal diet with antibiotics and the normal diet without growth promoters. However, there were no effects of growth promoters and diet type on broiler performance at 42 days.