Canada's first national fertility survey, carried out by telephone in 1984, found that 68 percent of all women aged 18-49-73 percent of currently married women, 69 percent of the previously married women and 57 percent of single women--are practicing contraception. Overall, the most widely used method of birth control in Canada is sterilization (male and female), which is relied on by almost 60 percent of all married users and 66 percent of previously married users. Among single women, the preferred method is the pill, chosen by seven out of 10 of such users. Among all women, the major determinant of method choice is age: The pill is overwhelmingly chosen by women under 25, and sterilization, by those 30 and over. While the IUD and the condom are used by roughly 10-14 percent of women in their 20s who practice contraception, these methods decline in importance with increasing age. Highly educated women are less likely than those with little education to elect sterilization, and more likely to rely on barrier methods. Differences in contraceptive prevalence and patterns of use between Catholics and Protestants have all but disappeared in Canada, but church attendance and country of birth appear to exert a modest influence on method choice. As might be anticipated, women whose family size is complete have considerably higher levels of contraceptive use than those who expect to have more children. The survey reveals no difference in contraceptive use between Quebec women and those in the rest of Canada, thus confirming both the accuracy of earlier Quebec studies showing extremely high levels of sterilization and the applicability of these findings to all other Canadian women.(ABSTRACT TRUNCATED AT 250 WORDS)