The article undertakes the analysis of the presence of natural law norms in matrimonial canon law contained in the Code of Canon Law of 1983. The Church has its own legal system, and pointing to the sources of individual legal norms is still a topical issue. Natural law as one of the sources of human law is present in the marital law of the Catholic Church. In the definition of marriage, the church legislator points to natural law directing spouses to procreation and education of children. The law of nature is visible in the objectives of marriage, but also in various psychological conditions influencing the decision about marriage, as mentioned in can. 1095, as well as the error regarding the person mentioned in can. 1097 §1 of the Code of Canon Law. Certain impediments resulting from the invalidity of the sacrament also arise from natural law. This is an impediment of kinship in the direct line and in the second degree of collateral line, as well as an impediment of age, because the nature of marriage requires the spouses to achieve appropriate physical and mental maturity.