This article analyses the political effects of the mixed parallel electoral system in Lithuania. According to the 'best of both worlds' logic, mixed systems could combine advantages from both the majoritarian and proportional formulas. However, counterarguments were also presented in the literature, pointing to the possibility of the ‘worst of both worlds’. According to presented analysis of Lithuanian parliamentary elections between 1992 and 2016, the pessimistic scenario is expected when a mixed parallel electoral system is used in a new democracy with a weakly institutionalised party system and high volatility. Lithuania's mixed parallel system produces relatively disproportional election results. However, it also facilitates the fragmentation of party system. Moreover, the effects in a concrete election are hardly predictable, especially the seat bonus of election winner. Evidence in the article points to a conclusion that mixed parallel electoral systems could contribute to the 'worst of all worlds' and new democracies should avoid them., This article analyses the political effects of the mixed parallel electoral system in Lithuania. According to the 'best of both worlds' logic, mixed systems could combine advantages from both the majoritarian and proportional formulas. However, counterarguments were also presented in the literature, pointing to the possibility of the 'worst of both worlds'. According to presented analysis of Lithuanian parliamentary elections between 1992 and 2016, the pessimistic scenario is expected when a mixed parallel electoral system is used in a new democracy with a weakly institutionalised party system and high volatility. Lithuania's mixed parallel system produces relatively disproportional election results. However, it also facilitates the fragmentation of party system. Moreover, the effects in a concrete election are hardly predictable, especially the seat bonus of election winner. Evidence in the article points to a conclusion that mixed parallel electoral systems could contribute to the 'worst of all worlds' and new democracies should avoid them.