One of the most important functions of the banking sector is to fulfill financial intermediation by establishing important connections between savings and investments. Banking activities have an accelerating effect on economic growth. For this reason, the relationship between financial activities in the banking sector and economic growth has been subject to many empirical studies. In this study, the relationship between banking activities and economic growth, which is one of the important discussion topics in economics literature, is being tried to be determined for Turkey. In order to determine the relationship between bank credits- deposits and GDP, three-monthly data for the period 2002:1-2015:4 have been used in this study. Time series model estimation, cointegration test and causality test were used in the econometric analysis. According to findings, there is a bidirectional causality relationship between bank credits and GDP in the long-term, but no causal relationship between deposits and GDP.