EXCLUSIVE

Henry Hill -- the former mobster whose life story became the basis for the movie "Goodfellas" -- died today at the age of 69 ... TMZ has learned.

TMZ spoke with Hill's girlfriend Lisa ... who told us Hill passed away in an L.A. hospital Tuesday after a long battle with an undisclosed illness.

Lisa tells us, "He had been sick for a long time ... his heart gave out."

We're told Hill had focused on mending relationships with estranged family members in recent years ... and Lisa tells us he had made tremendous progress before he died.

Hill leaves behind two children.

Hill was famously portrayed by Ray Liotta in the 1990 classic "Goodfellas."