Turkey is a foreign-dependent country on fossil fuels in the way of both daily life and industrial occupancy. The prices of fossil resources have the potential to have serious effects especially on the economy and financial markets. In this connection, it is noteworthy for investors and policy makers to examine the factors that may affect financial markets and to reveal the relationship between them. The aim of the study is to examine the effect of international fossil fuel prices on the stock market index. Yearly data were used in the study covering the period 1986-2019. BIST100 index as dependent variable and international crude oil, natural gas and coal prices as independent variables are analyzed. As a consequences of the analyzes made within the framework of ARDL Bounds test, it was determined that there is a co-integrated relationship between the variables. In addition, in the long term, it is determined that there is a positive and significant relationship between the stock market index and oil prices, a negative and insignificant relationship with natural gas, and a negative and significant relationship with coal. According to the error correction coefficient, imbalances occurring in the short term are eliminated in the long term. According to the error correction coefficient, disequilibrium occurring in the short term are eliminated in the long term.