The present study was conducted to determine the effect of dietary supplementation of organic acids combined with synergistic components, using a commercial product Lumance™ (Innovad NV, Belgium) containing esterified butyrins, propionic acid and sorbic acid, with medium chain fatty acids (capric, caprylic, and lauric acid) and plant extracts, on the productive performance and mortality of growing broiler chickens. A total of 492, one day old broiler chicks (Ross 308) were randomly allocated to four experimental treatments either with an unsupplemented control or 0.05, 0.1 or 0.15% organic acid mixture in a pelleted corn/soyabean meal diet, which were offered ad libitum until 35 days of age. Results showed that birds in the 0.1% supplemented diet group gave significantly higher (P < 0.05) body weights during the first two weeks of age and increased weight gain during the first three weeks of age. The inclusion had no effect on broiler mortality.