Monteno wrote songs for other performers as well, most notably Zdravko Čolić, Toše Proeski, and the rock band Indexi.

[2] During World War II, he was drafted and deployed to occupied Yugoslavia in 1945 where he met a Bosniak woman named Bahrija in Sarajevo and fell in love.

[4] Osvaldo's Italian wife gave birth in 1946 to a daughter named Daniela, Monteno's half-sister.

In a February 2014 interview, Monteno said that "Nije htjela" (She Did Not Want To) was written about a famous Yugoslav musician's wife, who was in love with another singer.

[14] Monteno was diagnosed with diabetes in the late 1990s and received three-hour dialysis twice a week at the University Hospital Centre Zagreb.

A performance at the 2012 Split Festival that summer was cancelled due to health issues[18] and rumors of his death circled the internet on 10 October 2012, even being picked up as fact by media in the region.