The new Act on occupational health services, implemented in 2002, imposes new tasks for occupational health services. The municipal occupational health services are a cornerstone of the foundation of the Finnish legislative system for occupational health services. The objective of the study was to explore how multi-municipal networking could strengthen the foundation. Nine public occupational health service units, lead by the municipal "The Occupational Health Services of Oulu" project, reflected collectively the advantages and disadvantages of multi-municipal networking during 1998-2000. Based on the qualitative analysis of the thematic interviews of occupational health service professionals it was found that the networking would be successful only if 1) The rules of the networking will be clearly explicated, 2) the funding of the net will be granted, 3) the networking will be integrated in the basic routine work, 4) there are enough communication in the net, 5) the public image of the net will be taken care of, 6) the networking will be directed in a systematic way, 7) the outcomes of the networking will be evaluated and 8) if the specific nature of all the partners will be respected.