In this collaborative study four clinicians, one each from Jaipur, Imphal, Madras and Varanasi, surveyed a total of 100 consecutive families of patients with enterobiasis. Perianal cellophane patch smears were taken on 4 consecutive mornings for diagnosis using a special Japanese device. All members of the patients’s family were persuaded to take the test. If one or more of other members were infected, the family was labelled an “infected family”. From this, Family Infection Raie (FIR) was calculated as :(number of infected familiesl total number of families) xl00. In addition Family Infection Extent (FIE) was calculated as :(number of infected members/total number of members) x 100. FIR was 80% and FIE ranged from 50 to 75%. These findings indicate that in 80% of the families of patients with enterobiasis one or more of other members are infected.