Thanks JPMessina44 that's pretty much what I thought. As you said it is highly unlikely that he would have had to renounce his Italian citizenship ( although he never applied for an italian passport ) since he was born in the USA they would never have ask this of him.

Do you know any good ...

In 1938 my Grandfather natualized in the USA, his son was born in 1935 in the USA. Does this mean I cannot claim Italian citizenship if my Dad was a minor when his father naturalized?

One further peice of information, my father served in the US Marines during Korea, but he never renouced his ...