Microbiological monitoring of the hospital environment is addressed either in regulatory texts or in recommendations issued by official bodies (circulars on air or water quality, among others), learned societies, or professional groups (guides to best practices). As part of environmental surveillance, microbiological sampling is one component of a suite of measures that includes monitoring the technical maintenance of facilities and equipment and verifying compliance with procedures; these measures collectively help control the hospital environment with regard to infection risk. Under the auspices of the French Society of Hospital Hygiene, a survey was conducted during the first quarter of 2000 to assess attitudes and practices regarding microbiological testing of water, air, and surfaces. The results are based on data provided by nearly 500 healthcare facilities. (R.A.)