The aim of this study is to determine the items in Science and Technology and Mathematics subtests of 6th, 7th, and 8th grades in the 2009 LDE, which was performed to select the students for the secondary schools, exhibited item bias with regard to student gender. Mantel-Haenszel (MH) method was used in order to determine the differential item functioning (DIF) of the items in the tests. The study was carried out with 22624 students in total, 6913 of whom were 6th year students (3614 males and 3299 females), 6333 of whom were 7th year students (3277 males and 3066 females) and 9374 of whom were 8th year students (4290 males and 5084 females). When the Science and technology subtest items are examined, it is seen that 2 (items number 6 and 16) in 6th grade, 3 in 8th grade (item number 14, 15, and 17) tests have B-level DIF. Among those five items 3 are favoring girls and 2 are favoring boys. In Mathematics subtests, item number 3 in 6th grade, item number 3 in 7th grade, and items 2 and 6 in 8th grade have DIF at B level. While 3 of those items work in favor of males, remaining 1 item works in favor of females. Content experts are asked for their opinion on the items having DIF to explore if any of them are biased. Based on the expert reviews it has been concluded that none of them includes gender bias. (Contains 7 tables.)