Bystanders are reluctant to perform basic life support (BLS) because of fear of failure and of infection, especially with mouth-to-mouth resuscitation (MTM). A possibility to enhance willingness could be the giving of MTM or BLS instructions at a very early age to the potential rescuers. The study aimed to investigate the effectiveness of MTM with respect to ventilation and the time needed for performing 5 ventilations. In this study, MTM was performed on a mannequin by 57 children and adolescents aged 10 and 14 years. This study showed that 14-year-olds effectively perform MTM, reaching the recommended tidal volumes. Ten-year-old children have already developed sufficient motor skills for MTM with no significant time differences compared with the 14-year-olds. However, physical demands may be rather high at this age. Further long-term studies are needed to investigate clinical benefits of early teaching of MTM or BLS that may lead to international guidelines with low age limits.