Martinjak families are Croats and they are mostly from Sveti Ivan Zelina. In the past century, relatively most of Croatian residents bearing this family name were born in Zagreb and Sveti Ivan Zelina. In Dukovec in Zabok area every eighth inhabitant had the family name Martinjak.
Prevalence
About 560 people with faimily name Martinjak live in Croatia today, in 220 households. There were 520 of them in the middle of the past century, and their number increased by 10 percent. They are located in the most of Croatian counties, in 25 cities and 65 other places, mostly in Zagreb (130), Varazdin (30), Mihovljan in Krapina area (30), Lovrecan in Oroslavje area (25), and in Tomasevec (25).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over ten times, the first time 1906 in source Yearbook and Directory of Literary Society of St. Jerome 1906.