This article describes the theory, methodology, and effectiveness of three natural methods of family planning: rhythm by calendar, strict basal body temperature rhythm, and combination calendar-BBT rhythm. The author also appeals to family planning counselors to provide appropriate support and thorough teaching of the rhythmn method to those couples who choose to practice it and emphasizes that family planning counselors have the responsibility to present this method in a positive way when presenting alternatives to clients. For rhythm might be the method of choice for the woman whose cycles are on the longer, more regular side and for whom the abstinence during the fertile period would present no hardship to the couple's normal pattern of sexual relations. Contraceptive devices could be used as a supplementary measure during the fertile period. The necessity for the cooperation of both partners is, however, essential to the workability of the natural methods of family planning. High motivation, high knowledge of human reproductive physiology, and use of BBT all contribute to raising the effectiveness of the natural methods of family planning.