Difficulty to conceive or subfertility constitutes a major psychological burden. Assisted reproductive technology changed significantly the outcome of couples faced with subfertility. These techniques consequently increased tremendously our understanding of the mechanisms underlying reproductive failure and opened new perspectives for future interventions, not only to increase cumulative conception rates after ART, but also spontaneous pregnancy rates. Thyroid dysfunction adversely affects fertility. Many studies imply a role for immunology, including thyroid autoimmunity in conception failure. In this review we attempt to update the available information on the adverse effect of thyroid dysfunction and/or thyroid autoimmunity on subfertility and we propose a rationale for testing and potential treatment options.