I can't find anything else than that it's a Spanish Commando WW2 knife.
Here is one link i found. This one says nothing about WW2, that was another site but i cant find it right now. They had one up for sale. I can try and find it again.
Bayonet based Fighting Knives
Here is the WW2 reference. Looks pretty much like yours. WW2 Spanish commando fighting knife (07/12/2009)
I also have one of these knives, and it is supposedly used by Spanish Special Forces.
There is a photo with caption of one in a book called 'Combat/Survival knives'
by Leroy Thompson, which was published 15 - 20 years ago.
Last edited by Walkwolf; 03-04-2012 at 04:42 AM. Reason: Added photo.........
IMO this is a post WWII knife ...
They may well be post WWII. I bought my knife about 10 years ago,
as it was quite unusual, has a very interesting blade, and I'd never
seen one before. Since then I've only seen maybe 4 or 5,
including the one above...............
It's a poor design, really. It does not fit the hand well because
the grip/handle is too small, and rather uncomfortable.
I'd like to find a book or instruction manual on these
if one was issued, to find out how they were
supposed to be used.
I am almost sure this knife is more a sort of a survival knife than a fighting knife. The Kukri like blade tells that. It's much more efficient as a light chopping tool, skinning on so forth, than for combat/fighting. I can say i have some knowledge about both categories of knives.
It is a continuation of Spanish bayonet lineage,
with 'bolo' shaped blade...........