There is a very comprehensive explanation here : http://english.stackexchange.com/questions/112467/free-of-vs-free-from In general, "free of" is used to mean "without". "This writing is free of errors." "The car is free of defects." "Free from" means "escaped from" or "without need to worry about." You can "be free from your captor " in the first sense and "free from harm" or "free from hunger" in the second sense.