The objectives of the study were to compare the attack rate of leprosy among household contacts of lepromatous and non-lepromatous cases of leprosy and to identify factors resating to the occurence of leprosy among household contacts. The associating variables to be selected for the study included age at the first detection and registration, type ot index case of leprosy, relationship of patient, size of family and duration of contact. The study population was 68 index cases of leprosy and their 358 household contacts only 105 of which were developed leprosy. The data were collected from patients records, interviewing the secondary cases by administered questionnaires together with additional physical examination of household contacts of index cases. Data collection was conducted for four months from October 1986 to January 1987. The frequency, mean, standard deviation, specific attack rate, proportion and ratio of leprosy among each age-group, type of index case, sex of household contacts and size of family were applied for statistical analysis. The results of the study are as follows:- 1. There were no statistically significant differences between the attack rate of the children (age less than 15 years) and the attack rate of adults (age more than 15 years). (P=0.4443) 2. There were no statistically significant differences between the attack rate of male and the attack rate of female household contacts. (P=0.3936) 3. There were statistically significant differences between the attack rate of the household contacts of Non-lepromatous cases and the attack rate of the household contacts of Lepromatous cases. (P=0.0885) 4. There were no statistically significant differences between the attack rate of leprosy among household contacts from family of size less than or equal to 5 members and one from family of size more than 5 members. (P=0.3594) 5. With regard to the relationship to the index cases of leprosy in the family, 60 percent were sons or daughters. The results of this study, particularly on the risk factors relating to the occurence of leprosy among the household contacts of leprosy cases could be useful not only for further application to educate the patients, and their household contacts but also for the training of public health workers involved in the integrated leprosy control services. Their better knowledge and understanding, therefore, could result in early detection and treatment of new cases of leprosy so that it would be the great impact to the reduction of infectious cases who are the main sources of transmission of leprosy in the community.