The Catholic Church does not oppose tattoos in principle.
The Catholic Church
Most people who say it does cite, “You shall not make any cuttings in your flesh on account of the dead or tattoo any marks upon you: I am the LORD” Lev 19:28.
Catholics remain bound to the Torah’s moral law. The Catholic Church places great emphasis on the Ten Commandments as both moral and natural law. Of the Catechism’s 2,865 numbered paragraphs, 505 of them (more than 1 of every 6) (§ 2052–2557) address the Decalogue.
However, the Torah mitzvah against tattoos belongs to the ceremonial law, which does not bind Catholics, as Rabbi Paul told us, “Now if perfection had been attainable through the Levitical priesthood (for under it the people received the law), what further need would there have been for another priest to arise after the order of Melchizedek, rather than one named after the order of Aaron? For when there is a change in the priesthood, there is necessarily a change in the law as well” Heb 7:11–12.
After all, any Catholic who argues that the law against tattoos binds us also has to argue that the rest of the ceremonial law binds us, such as, “You shall not let your cattle breed with a different kind; you shall not sow your field with two kinds of seed; nor shall there come upon you a garment of cloth made of two kinds of stuff” Lev 19:19.
The moral and ceremonial laws appear together in the Torah. This law against mixing two kinds is the very next verse after, “You shall love your neighbor as yourself” Lev 19:18, which is most definitely moral law Mt 22:39.
We Catholics find God’s law for us in Church teachings. The Catechism says not a single word about tattoos. Neither does the Compendium. Neither does the Compendium of the Social Doctrine of the Church.
Judaism
Orthodox, Conservative and Reform authorities agree that Leviticus and subsequent Jewish tradition believe that tattoos violate Jewish law, based on, “You shall not make any cuttings in your flesh on account of the dead or tattoo any marks upon you: I am the LORD” Lev 19:28. Rashi says that the Hebrew phrase k’tovet ka’aka in that verse refers to permanent writing engraved on the skin.
Tattooed Jews are generally welcome to participate fully in synagogue life, based on the more general proposition that a Jew who transgresses any particular mitzvah may still participate fully in Jewish life. Some Orthodox synagogues may find it inappropriate for a tattooed Jew to lead services or read from the Torah, but there is no specific Torah prohibition against it.
Medical tattoos, such as those used to identify a location on the body for a medical procedure, such as tattoos on cancer patients used to indicate the correct alignment of radiation equipment are acceptable under the principle of pikuakh nefesh. Where there are alternative ways of marking the skin for medical purposes the approval of tattoos is disputed.
Reform Judaism formally rejects tattoos, but in recent years has indicated some acceptance of tattoos that affirm one’s Jewishness and connection to Jewish tradition.
Some Jews ask whether tattoos should be removed as a symbolic act of rectifying the original sin. However, removal by plastic surgery or the injection of dyes to cover a tattoo, may themselves violate Jewish law. Second Exodus recommends consulting the rabbi who leads their synagogue.
Tattooed Jews may be buried in Jewish cemeteries. Some individual burial societies may decline to bury tattooed Jews, but no Torah provision prohibits burying a tattooed Jew.