Background ː Femoral neck fracture is a common problem especially in young adults. There are different methods of fixation of unstable neck femur fractures in adults, some of which are accompanied by complications. Aim of study: A systematic review on the different methods of fixation of unstable femoral neck fractures in adults with clarifying the incidence of nonunion, avascular necrosis, displacement and other complications in each type of fixation. Methods ː A systematic review of literatures was conducted  on five studies  (306 patients )  published in literature in the  last 10 years using different methods of fixation with inclusion criteria including ː English literature, human studies  on adults aged 18-60 years with unstable neck femur fractures Pauwel grade 3. Exclusion criteria including ːin vitro studies, pathological and non united fractures in people aged below 18 or above 60 years with stable neck femur fractures Pauwel grade 1,2 Results: showed that Achieved union in management by osteosynthesis and primary valgus intertrochntric osteotomy using broad DCP showed better results than by other methods of fixation (cannulated screws , DCS, cephalomedullary nail) and by achieving union percentage of 92,7% as in (MP Singh 2008), the same percentage achieved by fixation by DHS as in (Frank Liporace 2008), followed by 92% rate of union achieved by fixed angle device (DCS or cephalomedullary nail) in (Frank Liporace 2008) Comparing complications in different fixation methods showed that complications are inevitable yet manageable, but higher complications rate associated with fixation of neck femur fractures using DHS by achieving 26,4% rate of nonunion and 26,4% rate of AVN in (carlos Roberto schwartsmann 2017) while rate of non union was 7,3% in valgus intertrochntric osteotomy by broad DCP and rate of AVN was 11% as in (MP Singh 2008). Summary and conclusion Management of unstable neck femur fractures in adults is done by means of direct fixation with cannulated screws, DHS, fixed angle device (DCS or cephalomedullary nail) or osteosynthesis and valgus intertrochntric osteotomy to avoid some adverse effects of the direct fixation methods,  so,recent studies showed that valgus intertrochntric osteotomy achieve better results than traditional methods with  less complications.