The validity of the condition of non-REMARRIAGE, as a legal act, has always been in dispute by the jurisprudents and lawyers. A number of scholars regard this agreement un- lawful, in virtue of deprivation of the right, as a whole, and the opposition to the mandatory rules. Others believe the obligation of waiving of REMARRIAGE's right, by man, is binding. In this article with explanation of the two opinions, with relying on some legal bases, and with emphasis on the social interest of family, and new comment on the woman's role in the common life, the validity of the condition as a private agreement in the conjugal period is proved. With respect to the legal effects of the condition, considering the importance of its violation and with regard to necessity of effective sanction, the theory of nullity of the REMARRIAGE is regarded a cogent argument, although the theory of right of cancellation is not regarded void of reason.