Pesticides become obsolete when they can no longer be used for their intended purpose because they have been banned on account of their prolonged impact on the environment and/or because they cannot be used due to age, deterioration or a change of specification of currently applied pesticides. This problem has been addressed by the Stockholm Convention on Persistent Organic Pollutants (POPs), which was ratified by most EU member states and many but not all non-EU countries from Central and Eastern Europe and the former Soviet Union. It entered into force in 2004. The Convention and the subsequent National Implementation Plans (NIPs) drawn up by signatories have addressed the problems to some extent, notably within the EU. Within the EU, producers have been legally obliged to manage obsolete pesticides (OPs), including organising their collection and destruction according to EU laws applicable to hazardous waste management. With EU enlargement, EU law has consequently become applicable to the new member states as well. The process has been accelerated by EU programmes such as PHARE or national programmes established by some member states. However, implementation of the provisions of the Stockholm Convention on their own is hardly sufficient to effectively deal with the risks associated with OPs. The Convention only deals with nine specific OPs (hereafter called Persistent Organic Pollutant or POP pesticides), which represent a small proportion of the total number that are obsolete. In addition, and in close geographical proximity to the EU, problems remain, especially in South-East Europe and the countries of the former Soviet Union.