This study was conducted to evaluate the possibility of white leg shrimp (Litopenaeus vannamei) culture twice a year in Nayband Agro-industry complex in 2010. Three earth ponds (0.8 ha) were selected in the farm which had similar conditions in terms of culture system, postlarvae age (PL12) and stocking density (37-38 PL m3). The first period of shrimp culture started from mid April and they were harvested in mid July after 93 days. The second period of culture started in mid August and shrimps were harvested from the ponds in early December after 110 days. Final weight, survival, total production and feed conversion ratio (FCR)in the first period of culture were 13.5 ± 3.12 g, 80 ± 2.27 percent, 3200 ± 27 kg and 1.2 ± 0.09, respectively. These factors were 17.5 ± 3.31 g, 85 ± 2.35 percent, 4500 ± 119 kg and 1.09 ± 0.05 for the second period of culture, respectively. The results of the present study showed that the number of culture days, final weight and survival of shrimps in the second period of culture was higher compared with the first period of culture. Better FCR in the second period of culture showed that the condition of culture in this period is better and more economical than first period of culture. There was 9600 kg shrimp in the twice a year production system that is three times more than common shrimp production system (once a year) in the shrimp farms of southern Iran.