A Compulsory Research Report Submitted in Partial Fulfillment of the Requirements for Award of the Bachelor of Laws Degree (LLB) of Mzumbe University.Family law is a part of private law as opposed to Public law. Matrimonial problems are dealt with under the Law of Marriage Act. That is individuals in conflict refer their matter of Boards or civil courts are get their remedy. That way, intimacy is maintained and family life continues. However, there are instances where certain wrongs in private life are resolved through criminal justice system. Consequently resulting into imprisonment or paying heavy fines. For example, the LMA refers the relationship of persons in the foregoing to as a prohibited relationship; the Penal Code creates an offence known as incest to blood related persons having sexual intercourse. The study mainly aimed to check the enforceability of family matters by using criminal sanctions in Tanzania specifically dealing with the merits and limitations. And to deal with the importance (merits) of criminal sanctions as the one among the ways of regulating family matters arising within our societies but also to discover what will happen if family issues may not be regulated by criminal sanctions (demerits). The study involved a documentary review (books, journal articles and decided cases). This study found out that, the penal code and the LMA are two regulating legislations of family matters although the two legislations are not of the same dominions. But they work as if they belong in a same dominion of civil matters. Also, the LMA and the Penal code, both legislations do punish the offenders who has committed wrong relates to family matters (matrimonial issues). Through the two legislations an individual can be punished as he has been punished by the other.