Consumer Price Index (CPI) measures the changes the current retail prices of commodities purchased by a group of consumers over a given time period. 2003 based CPI is aimed to calculate the inflation rate by using the change of the prices of goods and services existed in the market. For this purpose, expenditures of households, foreign visitors, constitutional population and all the final monetary expenditures are taken into account. This concept left the owner occupied housing and expenditures from household production out of the coverage from the consumption expenditures.In determining the weights and calculating the index, Target Based Individual Consumption classification (COICOP) is used and according to this classification expenditures are organized in 44 sub-groups and 12 major groups. 447 commodities are used in the compilation of the index. International and regional guidelines: There are no important differences between Turkey's methodology reported in the EUROSTAT and relevant international or regional standards.