A study of enteroviruses was carried out in 400 persons, making up 95 families in 15 residential areas of Lagos, Nigeria. The study period was November, 1962 to September, 1963. 1476 faecal specimens from the above persons were passed in primary cultures of monkey kidney, (cercopithecus aethiops tantalus). 238 viruses were isolated, of which 70 were typed as enteroviruses. 37 belonged to the polio group, 15 to the Coxsackie B group, and 18 were Echo viruses. A possible identity was found for some of the non-typable isolates by their association with typable isolates in families, residential areas and the community in general. The remainder were untyped by the methods used. The isolates were discussed in relation to their patterns in seasons, residential areas, and families, and their possible association with tribes, occupations and sexes. Their possible relationship to clinical disease in the community was evaluated, and the advisability of vaccination discussed. Alternative plans were described.