One of the dangers to economic safety comes from the disturbances in nominal economy. Subsequent, aft er the crisis of 2008, decrease of prices indicators in advanced economies as well as the troubles in implementing interest rates policy by the central banks, encourage to analyse the phenomenon of defl ation. Defl ation, contrary to infl ation, has much more modest explanation in economic literature. The main thesis of this text is that deflation is not strictly monetary phenomenon but results from global and country economic situation. The central banks should not be responsible so much to fi ght defl ation up. Defl ation should not be appreciated only negative since the drop of CPI or HICP down to -1%, if is not accompanied by GDP and employment decrease and speculation bubble, do not is dangerous to economic safety