BACKGROUND: Many young paediatric patients with severe dental caries receive dental treatment under general anaesthesia. Oral health-related quality of life (OHRQoL) can be evaluated to assess the outcome of dental general anaesthesia (DGA) treatment. The aim of our study was to examine the OHRQoL of young Lithuanian children in need of DGA treatment and analyse the impact of DGA treatment on children's OHRQoL. METHODS: We carried out a prospective clinical follow-up study on OHRQoL among all young Lithuanian child patients who received DGA treatment at the Lithuanian University of Health Sciences Hospital during 2010-2012. The study consisted of clinical dental examinations of patients younger than six years, data collected from their patient files, and an OHRQoL survey completed by their parents prior to the child's dental treatment. We conducted a follow-up OHRQoL survey one month after the DGA treatment. The Early Childhood Oral Health Impact Scale (ECOHIS) and its effect size (ES) served to evaluate children's OHRQoL, and the Wilcoxon signed-rank test served for statistical analyses. RESULTS: We obtained complete baseline and follow-up data for 140 and 122 participants, respectively (84.7% follow-up rate). Pain and eating problems among children and parents feeling upset and guilty were the most frequently reported impacts at baseline. The parents reported greater impacts on boys than on girls. The ECOHIS score decreased significantly (69.5%, p < 0.001) after DGA treatment, revealing a large ES for the child (1.6) and family (2.4) sections of the ECOHIS. CONCLUSIONS: The OHRQoL of young Lithuanian children requiring DGA treatment is seriously impaired. Dental general anaesthesia treatment results in significant improvement of the children's OHRQoL. The children's parents also greatly appreciate this treatment modality for its positive impact on the family's quality of life.