Hajdinjak families are Croats and they are mostly from Cakovec. In the past century, relatively most of Croatian residents bearing this family name were born in Cakovec and Prelog. In Nebojse in Pregrada area every third inhabitant had the family name Hajdinjak.
Prevalence
About 490 people with faimily name Hajdinjak live in Croatia today, in 200 households. There were 570 of them in the middle of the past century, and their number decreased by 10 percent. They are located in the most of Croatian counties, in 27 cities and 58 other places, mostly in Zagreb (55), Cakovec (55), Prelog (50), Nebojse in Pregrada area (25), and in Varazdin (20).
Outside Croatia
Family name Hajdinjak is present in 15 countries on four continents.
In the sources analysed in the project Acta Croatica so far, the name is mentioned over ten times, the first time 1902 in source Hartmann's General List of Apartments in Zagreb.