Index cards used for registering each person residing in the Netherlands in the register of births, deaths, and marriages. As of 1 January 1940 personal index cards had to be filed in the register of births, deaths, and marriages for all persons residing in the Netherlands, including people with a foreign nationality. The personal index cards were officially called 'personal family index cards' because the index card for the head of the household (generally the man) listed the children as well. Unlike the previous system of family index cards, children were also issued individual cards.
Personal index cards were issued at birth or upon arrival in the Netherlands. These cards followed the holders throughout their entire lives, at least as long as they lived in the Netherlands.