This paper investigates crystalline orientation in monolike silicon wafers and its effect on solar cell performance. Monolike silicon wafers from two different bricks cut from interior and corner region of an ingot were compared. The mono grain in the interior brick is nearly perfect, but there are some large oblong shaped sub-grains in the corner brick. The large sub-grains at corner brick wafers are oriented at (311), instead of (100) orientation. The (311) grains contain high density of dislocation and cannot be effectively textured by alkaline solution, therefore lowering the cell efficiency significantly. There is about 0.86% (abs) cell efficiency reduction on the monolike cells that contain large sub-grains.