We determined the values of apparent metabolizable (AME), apparent corrected (AMEn), true (TME) and true corrected (TMEn) energy of six corn hybrids for broiler chickens in phases 1-7, 8-14, 15-21, 22-28, 29-35 and 36-42 day-old birds, using the substitution method (40%) of reference diet with the test ingredient. Ross-308 male chicks (1,134) were allotted to metabolism cages and the number of birds per experimental unit was adjusted to suit each bird's density stage in the cage, using six replicates. Simultaneously, birds continue to fast for the determination of metabolic and endogenous losses for each study phase. The birds received water and food ad libitum during the experimental period. The birds were maintained in metabolism cages for seven days, four days for adaptation to the cage and food, and three days for excreta collection. The corn energy values were significantly lower only in the pre-initial phase (1-7 days). Thus, broiler feed formulations of AMEn values for corn of 3563 kcal/kg DM for 1 to 7 days and 3778 kcal/kg DM from 7-day-old birds are recommended.The agronomic characteristics of the corn had no influence on the birds energy levels.