This study aims to investigate whether money supply behaviour in Egypt is exogenously or endogenously determined using data from 2004 to 2019. It aims to identify the determinants of money supply in Egypt and the most important tools used by the central bank to manage it. The study employs the Johansen-Juselius test (1990) to examine the long-run determinants of money supply in Egypt and the error correction model to examine the short-run determinants. We conclude that real GDP, discount rate, budget deficit, and net foreign assets have significant long-term effects on money supply, whereas exchange rate and net domestic assets have no effects. We recommend higher degrees of cooperation between the Central Bank of Egypt and the institutions responsible for the formulation of financial and commercial policies. we also recommend that the central bank continue monitoring foreign assets and strengthen its supervisory activities on banking institutions.