Shadow economy is considered the most important economic problem which is still of concern to researchers for it is linked to all economic variables. It is found in all States with different economic patterns. But it is more widespread in developing economies includes a recipe for lawful activities and other illegal .And it exists in all economic levels and affect all social strata and in all ages. Despite its characterization as a phenomenon, it cannot be overlooked as a reality. Depending on that, this research tried to clarify the concept of the shadow economy, and identify its components. As well as, this research shows the most important macroeconomic indicators in Syria and the impact of economic variables on the shadow economy.