In order to define monetary aggregates, we must first define money and liquidity. Money is one of the fundamental drivers of all economic processes. We can define it as good that serves as means of exchange, measure of value and value presevation. While liquidity is the ability of assets to turn into currency. Monetary aggregates are groups of financial forms of the same degree of liquidity. They measure the total amount of money in the circulation. Absolutely liquid assets are currency while all other monetary aggregates are less liquid assets and are therefore classified into individual monetary aggregates. Because of the various degrees of liquidity they can be used differently to pay their owners obligations or as savings forms. The structure of monetary aggregates consists of monetary aggregates M0 or primary money, M1 or coinage in the narrow sense, M2 or quasi-money, M3 or other liquid assets and M4 or total liquid assets. Since the independence of the Republic of Croatia, the Croatian National Bank has begun to govern monetary policy, thus changing the definitions of monetary aggregates. According to the new Croatian National Bank definition, there are four monetary aggregates, namely monetary aggregate M0 or primary money, M1 or monetary mass in the narrower sense, then M1a or monetary mass and monetary aggregate M4 or total liquid assets, domestic assets NDAs that are a special monetary aggregate there.