The aim of the article is to analyse the Polish legislative system in the context of sources and effects of legislative inflation (increase in the amount of norms). According to Grant Thornton’s calculations, in the first three quarters of 2019, 17.4 thousand pages of new legal acts (laws, regulations and international agreements) were adopted in Poland. This is 5.9% more than in the previous record year. The state of legislative inflation reduces the effectiveness of legal regulation. Causes of this phenomenon may be both political and theoretical. When drafting a normative act, it is necessary to: establish the current legal status; define the objectives; establish alternative legal solutions; formulate forecasts of the legal and social effects of the new law; determine the financial effects; choose the best legal solution. Polish legislative process is based mainly on general rational decision making model, which does not prevent against legislative inflation.