Jajčinović families are Croats and they are mostly from Hrvatska Kostajnica area. In the past century, relatively most of Croatian residents bearing this family name were born in Hrvatska Kostajnica area and in Sisak.
Prevalence
About 150 people with faimily name Jajčinović live in Croatia today, in 70 households. There were 130 of them in the middle of the past century, and their number increased by 20 percent. They are only located in in 6 Croatian cities and 14 other places, mostly in Sisak (25), Zagreb (20), Bobovac in Hrvatska Kostajnica area (15), Petrinja (15), and in Novo Pracno (10).
Outside Croatia
At least one family with this surname emigrated from Croatia to the United States. Family name Jajčinović is present in four countries on two continents. The family name "Jajcinovic " is used by small number of people in the United States.
In the sources analysed in the project Acta Croatica so far, the name is mentioned few times, the first time 2007 in source Encyclopaedia of Croatian Surnames.