This paper reports the results of a research carried out on environmental performance in companies with an environmental management system registered under the EMAS regulation. By applying an empirical approach, the article analyses the trend of the environmental performance of a sample of 64 Italian companies pertaining to 6 different industrial sectors, which have achieved EMAS registration for at least three years. The trends of the environmental indicators included in the environmental statements, officially validated by a third party and traceable to a period of time before and after the registration, were collected and evaluated. In particular, the influence of the EMAS registration on the improvement or the worsening of the environmental performance was analyzed and thus the ability of this instrument to pursue continuous improvement, a founding principle of environmental management certification schemes. Data obtained indicate that in some cases, EMAS leads to an actual improvement of environmental performance, even in the short period.