This article attempts to measure and report the extent and magnitude of tax evasion by all kinds of enterprises in the Greek economy, for the period 2011–2017, utilizing the ‘single net profit ratios’, which were implemented in the past by the Hellenic Tax Authority in the context of tax audits. According to the research findings, the annual tax evasion for all Greek enterprises was calculated on average for the period 2011–2017, in terms of gross revenues concealment, at €57.5 billion (31.58% of GDP). Since 2011 there has been a strong steady decline in tax evasion of enterprises while on the contrary a steady increase has been recorded for sole proprietorships and self-employed.