PIP: Ecuador's total fertility rate (TFR) declined from nearly 7 to 3.6 during 1965-69, while contraceptive prevalence rose from 33.6% to 56.8%. The provinces of Ecuador were classified into three equal groups based on Bongaarts' index of contraception, and their fertility characteristics were compared. The 5 provinces in group III with relatively homogeneous indices of contraception were examined in this article. The index of contraception was 0.503 in Imbabura, 0.469 in Los Rios, 0.457 in Carchi, 0.456 in Tungurahua, and 0.430 in Manabi. The 5 provinces were all in phase 3 of the demographic transition, with TFRs of 4.44 in Imbabura, 3.68 in Los Rios, 3.78 in Carchi, 3.68 in Tungurahua, and 3.43 in Manabi. The index of contraception and TFR, respectively, were 0.435 and 3.61 for Ecuador. The fertility differentials in provinces with similar levels of contraceptive usage were attributable in large part to differences in age patterns of fertility, maternal educational levels, marital status, and prevalence of contraceptive methods. Age-specific fertility rates for women aged 15-19 ranged from 76/1000 in Imbabura to 114/1000 in Los Rios and Carchi. The difference between the average number of children of illiterate women and that of women with higher education ranged from 1.66 children in Manabi and 1.69 in Carchi to 2.97 in Imbabura, compared to the difference of 2.44 for Ecuador. The proportion of women single ranged from 30.4% in Los Rios to 39.9% in Carchi. Contraceptive prevalence in the 5 provinces ranged from 50.9% in Imbabura to 56.9% in Tungurahua. The differences were reflected in Bongaarts' indices of nuptiality and postpartum infertility as well as contraception.^ieng