In 2008, some general practitioners (GPs) in the area of Empoli (Tuscany Region, Central Italy), reported to the Local Health Authority (LHA), an unusually high frequency of leukemia deaths among their patients residing in a one of the municipalities of the area. The LHA decided to carry out an epidemiological investigation. An interdepartmental working group was set up, led by the Department of Prevention of the LHA, and made up of representatives of the Institute for Study, Prevention and Cancer Network (ISPRO, Florence), the G. Monasterio Foundation/ Institute of Clinical Physiology of the National Council for Research (CNR) of Pisa, the University of Pisa, the Regional Environmental Protection Agency and community members. Several epidemiological analyses were carried out (namely incidence and mortality analysis, assessment of the residential history of all cases and micro-geographical incidence evaluation, assessment and quantification of local environmental pressures, evaluation of congenital abnormalities). The investigation took over two years to be completed. The work agenda was shared with community members, who contributed to decision-making, study design and the communication plan. Thanks to the interaction with community members, researchers had the chance to become aware of their information needs and of local knowledge concerning the research issues. The final report was published online and presented to citizens in several public meetings. Direct involvement of the local community during project development was found to be useful to reduce the perceived distance between public authorities and the local population, as highlighted in the guidelines on cancer cluster investigations.