Background: Intramedullary nails may be used for the surgical fixation of extracapsular hip fractures in adults. They may be inserted from the top (cephalocondylic) or from the bottom (condylocephalic) end of the femur. OBJECTIVES: To compare different types or design modifications of intramedullary nails used in the fixation of extracapsular hip fractures. Search Strategy: We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (March 2006), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 1, 2006), MEDLINE, EMBASE, the UK National Research Register, several orthopaedic journals, conference proceedings and reference lists of articles. SELECTION Criteria: All randomised or quasi-randomised trials comparing different types of intramedullary nails or modifications to the design of intramedullary nails in the treatment of extracapsular hip fractures in adults. Data colection and analysis: Both authors independently assessed trial quality and extracted data. Additional information was sought from all trialists. Main results: Six studies, involving a total of 1071 predominantly female and older people with mainly unstable trochanteric fractures, were included. Allocation concealment was likely in one trial, not described in three and not done in the other two trials.Four studies, with 910 participants, compared the proximal femoral nail with the Gamma nail. Though there was increased risk of comminution (fragmentation) at the fracture site when inserting a Gamma nail, there was no statistically significant difference in operative fracture of the femur (1/455 versus 5/455; relative risk 0.33, 95% confidence interval 0.07 to 1.63). No notable differences were seen between implants for fracture healing complications, reoperations and other post-operative complications. Pooled data showed no significant difference between implants for mortality (relative risk 1.08, 95% confidence interval 0.82 to 1.41) or function assessment outcomes.One study, with 80 participants, found no differences between a gliding nail versus a standard Gamma nail. Another study, with 81 participants, found no difference between a dynamically versus a statically locked intramedullary hip screw. Authors' conclusions: The limited evidence from the randomised trials undertaken to date is insufficient to determine whether there are important differences in outcome between different designs of intramedullary nails used in the internal fixation of extracapsular hip fractures. Given the evidence of superiority of the sliding hip screw compared with intramedullary nails for extracapsular hip fractures, further studies comparing different designs of intramedullary nails are not a priority. Any new design should be evaluated in a randomised comparison with the sliding hip screw.