The objective of the study is to investigate pain and distress experienced by a group of adolescents and children during peripheral intravenous cannulation in a paediatric emergency department. This cross-sectional study was performed between November 2019 and June 2020 at the paediatric emergency department of the Institute for Maternal and Child Health of Trieste, Italy. Eligible subjects were patients between 4 and 17 years old undergoing intravenous cannulation, split into three groups based on their age: adolescents (13–17 years), older children (8–12 years), and younger children (4–7 years). Procedural distress and pain scores were recorded through validated scales. Data on the use of topical anaesthesia, distraction techniques, and physical or verbal comfort during procedures were also collected. We recruited 136 patients: 63 adolescents, 48 older children, and 25 younger children. There was no statistically significant difference in the median self-reported procedural pain found in adolescents (4; IQR = 2–6) versus older and younger children (5; IQR = 2–8 and 6; IQR = 2–8, respectively). Furthermore, no significant difference was observed in the rate of distress between adolescents (79.4%), older (89.6%), and younger (92.0%) children. Adolescents received significantly fewer pain relief techniques.Conclusion: This study shows that adolescents experience similar pain and pre-procedural distress as younger children during peripheral intravenous cannulation. What is Known:• Topical and local anaesthesia, physical and verbal comfort, and distraction are useful interventions for pain and anxiety management during intravenous cannulation in paediatric settings. • No data is available on pain and distress experienced by adolescents in the specific setting of the emergency department. What is New:• Adolescents experienced high levels of pre-procedural distress in most cases and similar levels of pain and distress when compared to younger patients• The number of pain relief techniques employed during procedures was inversely proportional to patient’s age, topical or local anaesthesia were rarely used