The aim of present study is comparing the analgesic effect of ketamine infusion with nebulized fentanyl for control of pain in patients with long bone fractures in a double-blind randomized clinical trial, in participants admitted to the emergency department of Imam Khomeini and Golestan hospital of Ahvaz in 2016-2017. Inclusion criteria: age 18 to 55 years, exclusion criteria: passing more than 24 hours of fractures, fractures avulsion, head injury, a history of smoking or drug abuse, pregnancy and lactation, signs of alcohol drinking or consumption, loss of consciousness, difficulty in breathing, allergy to ketamine, and a history of seizures. After obtaining consent, eligible patients will be divided randomly into two groups (each group 68). For first group 5 mL of saline intravenously and 4 mg/kg of solution, 50 micrograms per ml of fentanyl that its volume with normal saline arrives to 5 cc, receive with nebulizer and for the second group 0.4 mg/kg ketamine will be infused within 10 minutes. Pain intensity will be recorded by visual pain scale (VAS) before and (5, 10, 15, 30 and 60 minutes) after intervention. If pain is not controlled or sustained after interventions, additional painkiller will be prescribed and information will be recorded. Finally, medication side effects (nausea, vomiting, hallucinations, difficulty breathing and drowsiness) will be evaluated in patients.