The monograph is concerned with gaining an insight into the relationship between ethnic identity and population behaviour in the Philippines Establishing the linkage between ethnic diversity and fertility differentials will have definite implications for population policies and programmes This interest grows from the general recognition that such policies and programmes have often been planned and implemented on a national scale with little consideration for ethnic diversity While the relationship between ethnicity and fertility will not be directly studied or measured in this manuscript inferences and hypotheses will be drawn from an integration of available literature on the various ethnic groups in the Philippines on the one hand and a review of relevant population data from existing surveys on the other