The key rate is the rate on loans and deposits, which is determined by the Central Bank of each country for a certain period. The rate of inflation depends on the level of the key rate: with an increase in rates on deposits and loans, the demand for goods decreases and, at the same time, inflation decreases. With a decrease in the rate on deposits and loans, the population takes more loans, investing more, which leads to an acceleration of inflation. The purpose of the study is to determine the correlation between the values of the key rate and the inflation rate in the Russian Federation. A number of tests were carried out for the presence of Granger causality, for cointegration; studied ARIMA models for forecasting the key rate and VAR for inflation.