This study was done in order to determine the primary school students difficulties and their reasons in learning biology concepts presented in science curriculum in Turkey. 23 topics were compiled from the published syllabuses of Ministry of National Education and commonly used science textbooks.This topic headings were presented to 476 (256 7th grade and 220 8th grade) students to determine their difficulties in learning of biology concepts. İt has been observed that students have a difficulties in the topics of cell division,animal and plant tissues, regulatory and control systems, living organisms and ATP energy and genetics. The reasens of learning difficulties were established as absence of experiment, uninterested, learning by heart.