The article deals with the issue of voting overreporting in social surveys. The comparison of voter turnout reports in public opinion polls to official statistical data often shows great difference. Respondents answer that they voted or would vote whereas they actually didn’t. The culprit of this effect is social desirability bias i.e. reporting false attitudes and behaviours in a manner that is consistent with social norms. As a result analyses of voting behaviours have systematic error. The article presents methods for reducing social desirability bias which include: choice of research techniques which assure anonymity and confidentiality, question wording which lowers social pressure to give false answers, indirect questions, double-rating method, randomized response technique and making post hoc corrections.