A comparison was undertaken of the environmental monitoring occurring in four EU cities. This aimed to establish the nature and pattern of the monitoring activity at the local level across environmental media and also the accessibility of the results to third parties. Significant differences are found in both the pattern of what is monitored and also the methodologies used. The arrangements for access to data very widely. Reasons for the differences in monitoring at the local level are considered and the implications for making international comparisons, especially of compliance with legal requirements, are discussed.