Previous studies have shown that runners differ in terms of sociodemographic characteristics. However, given the increase in participants at running races, the question arises whether these sociodemographic differences have been erased and if the second running boom has democratized running. An online questionnaire was sent to a randomized sample (n = 2378) of finishers at the 2017 Gothenburg half marathon (Göteborgsvarvet). The self-reported sociodemographic variables were then compared to Swedish national averages. The results show that Göteborgsvarvet finishers are considerably more likely to be men, well-educated and employed, compared to the general population of Sweden. This study indicates, therefore, that half marathon finishers are still distinctly different in terms of sociodemographic variables compared to the general population. These differences need to be taken into consideration when conclusions are drawn concerning running and its health effects on runners.