Can you use turkey instead of ham in chicken cordon bleu?

It will work out. It might not give it the exact same flavour profile but it will still be tasty as I've already tried versions using smoked turkey before with fantastic results. Trying it with beef "bacon" is also an alternative.

Smoked turkey sounds wonderful.

You can make it with turkey or turkey pastrami as Bevi and Pegeen suggested, I think that there is nothing wrong with using either or just using an herbed cheese, what about a turkey bacon?

You can make anything work, assuming you're not in a Classics contest of some sort. Never give up - but do test ahead if you can, when departing from the classic ways.

I absolutely support and respect the orthodox preferences of religious friends. But there are some things that just can not be fixed with substitutes. To make it stranger, among my friends the ones who relish pork possibly even more than I do are Jewish. I still haven't figured that part out. But chicken cordon bleu is a tradition of it's own and reinventing it with turkey is unlikely to give you good results.

Try a smoked turkey to add flavor.

p.s. Turkey is also much more bland than ham, so you'll probably find that you need to add some herbs at some point in the recipe. Again, it would be helpful to see the recipe. I love Chicken Cordon Bleu... bon appetit!

Yes, but... turkey is leaner so you won't get the basting/fat properties of the ham. It would help to see your recipe, but consider using more cheese and definitely roasting for less time. This is one of those substitutions where it might be a very good idea to try the recipe in advance of your actual dinner.

I use turkey pastrami - but I'm a kosher consumer, so we think it's fine, it will depend on the taste experience of your guests.