On occasion. The problem with relying on it as a front line defensive fortification at any rate is by this point modern artillary and bombers had far passed the point where it could easily shell bomb a castle wall to rubble relatively quickly so you couldn't necessarily expect a castle to be anything of a formidable defence. However they were used occasionally. Away from the front occasionally old castles saw some use as POW camps and the like such as Colditz. If you mean in combat specifically there were a few castles in Italy that were integrated into the Gothic Line defences by Axis forces. For example the swift capture of Castle Aghinolfi was one of the more famous feathers in the American 92nd Infantry, the Buffalo soldiers. Some held out a little better with the structures surrounding Monte Castello di Vibio (which was more of a medieval fortified town than a true castle but close enough) was held by German forces tenaciously in the face of the American and Brazilian (The first major engagement of the Brazilian expeditionary force) attacker until the ultimate break through as the allies worked their way up the side of the hills, though in this case the steep natural terrain played as much if not more of a role than the medieval fortifications.

As a side affect though a lot of castles ended up getting badly damaged or destroyed in Italy during the war as a result of this.