The transition of contraception use in Colombia was an important moment when health and fertility were tightly associated with social behavior. Multi-level multi-process (duration and method choice) life history analysis of contraceptive use allows the identification of determinants. Individual trajectories show many successive spells of adopting or ceasing contraception. Younger women displayed discontinuous behavior with a large proportion of total fertility (which itself has been decreasing since the mid-1960's) concentrated in the earliest ages. After the pioneer generation of 1935-40, the generations of 1955-59 and 1960-69 mastered contraception, the generation 1970-79 used contraception for spacing. Contraception was strongly associated with material life condition, with education taking a secondary role. Son (or girl) preference appeared to be absent. Contraceptive methods were examined for their influence on intermittent behavior as a particular method might be used for only a short period. The pill and male condoms were the preferred method of adopters; users of male condoms were the less likely to cease, users of traditional methods the most likely to cease. The model highlights the trade-off between the desire to comply to the traditional social norm of a large family and the desire to adopt a modern way of life corresponding to a smaller family.