Two major protocols of non-randomized clinical trials of the efficacy of the Lactational Amenorrhea Method of contraception (LAM) were performed in the 1990s that suggested LAM to be a highly effective albeit temporary method of contraception. Data from a longitudinal study of over 4000 breastfeeding women performed by the World Health Organization provide supporting information as to the efficacy of LAM. Effectiveness data are scarce, as is information on the use of LAM in industrialized countries. Issues surrounding LAM efficacy and effectiveness are reviewed, and the existing information from industrialized countries is highlighted.