Background: Intranasal (IN) fentanyl provides rapid and powerful non-parenteral analgesia in the ED. A concentrated solution of fentanyl (300 mg/mL) has been used in prior trials, yet many ED use the standard solution at a concentration of 50 mg/mL, which is widely available and of low cost. We set out to determine if this lower concentration of fentanyl is also efficacious. Methods: Prospective audit in children aged 5–18 years presenting with upper limb injuries. Patients received IN fentanyl (50 mg/mL) at 1.5 mg/kg. Patient assessed pain scores were collected 5, 10, 20, 30 and 60 min following IN fentanyl administration using a visual analogue scale or Bieri Faces – Revised scale. Parental scores were used if patients were unable to provide a score. Results: Of the 59 eligible patients, 36 were enrolled; median age was 6.8 years (range 5–15 years), and 89% (32/36) ultimately required fracture reduction. Median first dose of IN fentanyl was 1.4 mg/kg. Median pain scores dropped from 7 (interquartile range 5–10) pre-fentanyl to 5 (interquartile range 4–8) at 5 min and 2 (interquartile range 1–4) at 30 and 60 min. A total of 21 (58%) children did not require further analgesia in the ED. There were no adverse events. Conclusions: Standard i.v. concentration IN fentanyl (50 mg/mL) appears to have analgesic efficacy in children with upper limb injuries.