Yes, in general, prenuptial, or antenuptial, agreements are valid. The theory is that each party willingly entered into the agreement and, as such, are contractually bound. However, if a court determines that a party did not willingly enter into the prenuptial agreement or the agreement was based on fraud, then the agreement will not be enforceable. For example, a party can contest a prenuptial agreement if he or she did not receive full and frank knowledge of all available assets of the other person. Likewise, a party can try to contest the validity of such an agreement if the agreement is too one-sided or unfair as to be considered unconscionable under state law.