This project work seeks to do an appraisal of open market operation as a tool in controlling inflation in Nigeria. The three objectives of the study includes:To find out the extent to which open market operation has helped in controlling inflation in Nigeria, to access the problems encountered in using open market operation as a tool in controlling inflation and to make meaningful recommendation.The sample size was 152 from the Central Bank of Nigeria Okpara Avenue Enugu Sample techniques were the systematic controls, the researchers used in carrying out the work. Method of data collection was the questionnaires used to derive information from the various respondents to which includes both senior and junior staffs. In validity the researchers’ submitted their instruments to the three experts after going through it approved that the instrument was suitable for what the researchers are seeking. The method of analysis was the percentage.The findings entails that through the selling of securities to commercial banks inflation can be controlled.Buying of the securities from the commercial banks is a means of controlling inflation in Nigeria and through the control of liquidity by the central bank. Government should go on with open market operation as a tool to control inflation, because this is the best monetary policy that has been employees.It should try to maintain the standard laid down rules, so that the desired targets should be attained. There should be a way for maintaining stable prices for food commodities or food stocks and other items.