In spite of constant efforts by health and social workers, existing family planning measures are not used by a vast majority of eligible couples. This is because of the fear that the method may affect their health and happiness. Billings' ovulation method is based on the scientific observation that by noting the changes in cervical mucus, which is clear, slippery and copious in periovulatory period, it is possible to prevent pregnancy by avoiding intercourse during this period. As this method does not require the use of drugs or devices it was decided to promote this method in the urban areas and slums of Patna, Bihar where couples were not using other methods. This is not a comparative study of the cost-effectiveness of Billings' ovulation method versus other contraceptive measures at all. An analysis of 501 cases (267 in urban and 234 in slums) over a period of 2 1/2 years has been presented and it is gratifying to note that the couples from all religions and strata of the society (nearly 47% were slum dwellers) agreed to continue this method.