We have started to teach natural family planning (NFP) in our health centers. We have studied 218 cycles in 14 women using NFP to space or avoid pregnancies for an average of 15 months per woman. All women were taught the symptothermal method, and used temperature, mucus, calculations and cervix modifications; temperature, calculations and mucus; or mucus alone, as signs of fertility. Usually they kept track of signs of fertility in each cycle; temperature taking was frequently limited to the periovulatory period, when they noted changes in their mucus. User couples belonged to a middle-lower economic group, for whom motivation was not religious or ethical. Good information is essential in deciding to use NFP. Women who are satisfied users often inform other women. User couples easily become autonomous and acquire the required level of knowledge, abandoning methods they relied on previously. Autonomy is welcomed by these women.