The impact of metropolitan dominance on the diffusion of family planning in the Philippines was analyzed. Hypotheses based on the diminishing effect urban centers have on knowledge approval and practice of family planning as distance from the metropolitan core increases, size of the local urban center decreases and level of individual cosmopolitanism increases were tested by means of bivariate correlations. In addition the predictive value of these variables was assessed by chi-square and gamma coefficients. The findings indicate, 1) a decreasing linear relationship between metropolitan dominance and the diffusion of family planning variables; 2) a curvilinear relationship between size of local urban center and the diffusion of family planning; 3) a decreasing linear relationship between level of individual cosmopolitanism and the diffusion of family planning. Furthermore, the findings indicate that the distance from the metropolitan core effect is vitiated when the size of the local urban center exceeds the 20,000. However, the distance from the metropolitan core effect is not conditioned by the level of individual cosmopolitanism.