Short answer - nope. Long answer - you can make them work, but I'm not sure it's worth it. The retaining slot in the mags are different. The Keltec mag will not seat high enough in the LCP for the slide to strip the round. I did get one to work by soldering a small piece of metal to the slot, wasn't easy to do, but I read the same article and already bought the mag, couldn't return itNietz said:While I was looking around on the net I came across this http://www.killacomputer.com/Article_Detail.php?g=content1208767637 page and he says that the LCP will use P3AT magazines but not vice versa, anyone have both and try this out to confirm if it does work? now this is really more of curiosity, but maybe a way to have a 7 round mag as well if the Keltec with the +1 extension would fit.