The authors consider the problem of limited supply of candidates for mayors. Since 2002, most electoral committees in Polish municipalities have only participated in the elections for municipal councils and not for the principal executive office. Between 2002 and 2010, there was also a growing share of municipalities in which only one candidate ran. The logistic regression analysis demonstrates that the electoral committees’ decision whether or not to nominate a candidate is influenced by their size (popularity), as well as the size of the municipality. If there is a dominating committee and competing incumbents, it is less probable that another candidate would run. It is evident that the well-known effect of incumbency advantage works not only during the elections but also before them (when candidates are registered).