Although high on the international forest agenda, illegal logging is often ambiguously defined and there is considerable uncertainty about its quantitative and qualitative characteristics. This obscures assessments of its social, economic and environmental impacts and precludes informed policy conclusions. Through timber export statistics, estimates of the domestic timber consumption and official harvesting records, the extent of illegal logging and its breakdown to origin, felling agents and species groups is estimated for Ghana over the period 1996–2005 based on a definition that emphasises the violation of established forest management regulations. Of the total harvest, 70% or 2.3 – 2.7 million m³ annually is estimated to be illegally cut. Chainsaw operators, who supply most of the domestic lumber demand, account for two-thirds and the export oriented timber industry account for one-third of the illegal harvest. The most valuable timber species dominate the illegal harvest and they appear to originate mostly from forest reserves, which as a consequence are seriously threatened. Eliminating illegal logging will require positive economic incentives for rural people to protect and grow timber trees. This, however, calls for fundamental reform of the timber governance system.