Non-invasive methods of sampling and a range of immunological assays for mass ecologo-hygienic studies of population were developed and introduced into practice in Sysin Scientific Research Institute of Human Ecology and Environmental Hygiene of Russian Academy of Medical Sciences. The studied materials were saliva, urine, breast milk, the condition of lymph nodes, and anamnesis. The complex of non-invasive methods was shown to be less complicated and, at the same time, informative and cheap, which allows recommending it for sociohygienic monitoring when performing mass hygienic studies.