The Kyoto Protocol is praised by some scholars and criticized by others. This paper evaluates the enforcement mechanisms comprising monitoring and non-compliance procedures based on an informal game theoretic analysis. It is argued that the monitoring system has achieved an unprecedented level of sophistication. It also appears that the non-compliance procedures have achieved a remarkable quality (in particular when judged in view of past international environmental treaties) in terms of their deterrence potential and credibility, though there is room for improvement. Possibilities for improvement are outlined and possible supplemental non-compliance procedures are proposed.