Contraceptive failure is the primary cause of unintended pregnancy in the United States. With obesity rates at epidemic proportions, any association between obesity and strategies that prevent undesired pregnancies constitutes a significant public health and economic concern. Unfortunately, the relationship between obesity and contraception has not been extensively studied. Evidence from several epidemiological studies suggests that obesity may increase failure of some hormonal contraceptives resulting in unplanned pregnancies. Obesity may make procedure-dependent contraceptive methods (i.e., sterilization and intrauterine devices) more technically challenging for the provider to perform. Hormonal contraceptives, on the whole, do not appear to adversely affect body weight and provide important noncontraceptive benefits (i.e., cancer protection). Some surgical interventions to treat bariatric issues may compromise the efficacy of orally dosed contraceptive methods. Overall, the Society of Family Planning strongly encourages the use of both hormonal and nonhormonal methods of contraception in obese women desiring pregnancy prevention with very few restrictions. Further studies are needed to determine the interrelationship between obesity and contraception. In addition, future contraceptive efficacy studies need to include women of differing BMIs to better reflect the population of women using these methods.