Experimental investigations have been carried out in this paper to study the enhancement of heat transfer characteristics for cross flow low integral finned tube heat exchanger with using of (MgO) nanofluid. The study includes designing and manufacturing of test section from Pyrex glass with dimensions (2505001200) mm width, height and length, respectively. has a single copper tube with eight passes.. The low integral finned tube with (19 mm) inner diameter, (21 mm) root diameter and (24 mm) outer diameter. The fin height is (1.5 mm), thickness (1 mm) and the pitch is (2 mm). Air was used as a cooling fluid passing across the test tube with a range of velocities (1, 2, 3 and 4) m/sec. The inner side flow rates with a range of (2, 3, 4, 5 and 6) L/min. for water and for nanofluid.