Provision of paediatric anaesthesia requires careful consideration of the child's cognitive state, unique body composition and physiology. In an observational cohort study, we describe the population characteristics and conduct of anaesthesia in children aged 2–17 years from 1 January 2005 to 31 December 2015. Children were identified from the Danish Anaesthesia Database. We recorded the following variables: age; sex; comorbidities; indications for anaesthesia; practice of anaesthesia; and complications. Results are presented for two age groups: 2–5 and 6–17 years. In total, 32,840 (61% male) children aged 2–5 years received 50,484 anaesthesia episodes and 91,418 (54% male) children aged 6–17 years received 141,082 anaesthesia episodes. The younger children, compared with the older children, were more frequently anaesthetised at a university hospital (50% vs. 36%) and for non-surgical procedures (24% vs. 8%). For both age groups, general anaesthesia was the primary choice of anaesthesia regardless of the reason for anaesthesia. For surgery, general anaesthesia using inhalational agents in addition to intravenous agents or alone was more frequently used in younger children (49% vs. 15%), whereas older children commonly received total intravenous anaesthesia (50% vs. 83%). Regional anaesthesia was infrequently utilised. Complications occurred in 3.3% of anaesthesia episodes among 2–5 year olds compared with 3.7% of anaesthesia episodes among children aged 6–17 years. In conclusion, we found younger children (aged 2–5), compared with older children (aged 6–17) were more frequently anaesthetised for non-surgical reasons, at a university hospital and using inhalational agents. Complications were rare.