This study was carried out on Gemlik variety olive plants (Olea europae L.) in branches cages with two different periods, from August to September and from September to December in 2009, at natural conditions in Adana. In this study, some biological characters of Palpita unionalis (Hubn.) (Lepidoptera: Pyralidae) such as adult longevity, female egg numbers, hatching period of eggs, larvae, prepupa and pupa longevity were studied. At the end of this study; average life span in nature was found about 38.4 days at 28.2 degrees C, 70.1% R.H at the first branch cages study and it was completed in 61.6 days at 18.4 degrees C, 64.4% R.H. at the second branch cages study. The duration of adult stage was determined as 6.17 +/- 0.41 (3-13) days in the first and 9.22 +/- 0.60 (3-21) days in the second study. The number of eggs laid per female were ranged from 4 to 638 (average 233) and from 29 to 643 (average 296) for the first and second study, respectively. Also, the eggs were hatched about 3.45 +/- 0.13 (3-5) days and 4.33 +/- 0.10 (4-5) days. P. unionalis adults were active at night and laid 2-28 eggs as single or in groups usually on the lower surface of leaves. The duration of larval stage development was 18.50 +/- 0.56 (16-20) days for the first, while the second was 26.25 +/- 0.82 (23-32) days. The average prepupa stage duration was found 1.63 +/- 0.18 (1-2) days in the first period and 1.73 +/- 0.35 (1-5) days for the second period. The pupa stage was also determined 8.63 +/- 0.60 (6-10) days and 20.30 +/- 1.92 (13-33) days for the first and second studies, respectively.