This study was designed to investigate whether isolation of the bed is necessary during flap prefabrication. A fasciovascular carrier was used to prefabricate a 3 x 8-cm epigastric flap in rats. The animals were divided into three groups of 42 each. During flap prefabrication, in group 1 (control), no bed isolation was done, whereas in groups 2 and 3, a thin silicone sheet was used to isolate the underlying bed from the flap and fasciovascular carrier partially or completely, respectively. In each group, 14 prefabricated flaps were raised at 3, 7, and 14 days after prefabrication. Flap survival was assessed at day 7 after flap elevation. In comparing to the survival rates of the prefabricated flaps for each time interval, there was no significant statistical difference between the control and experimental groups (p > 0.05). With further studies, including india ink injection study and microangiographical and histological examinations of the prefabricated flaps, it was concluded that, during flap prefabrication, isolation of the bed with a silicone sheet does not improve the survival of prefabricated skin flaps. Moreover, it may cause some complications, such as extensive seroma, infection, and exposure of the sheet, which further interfere with the evaluation of experimental results.