Passport confusion - please help!

[pegasusyt]

I am about to apply outland and still can't figure out which passport I should put down on my application.

 I have both argentine and spanish citizenship/passports. I have always used my spanish passport to enter canada.

I am concerned though that if the Buenos Aires visa office requests my passport at some point, and I send the spanish one instead of the argentine one, it may be confusing and cause problems?

Does anybody have any ideas?

Thanks in advance..

[pinklady]

I think you should declare both.

[pegasusyt]

thanks for replying - I am declaring both and sending copies of both with my application. but still not sure which to send it when req'd!?

[hsbalouch]

In my opinion you should use the Passport of the country you are applying from and want your case to be processed in, just for a safer side mention the other passport as well on a separate sheet of paper!

[CharlieD10]

You have to submit the passport relevant to the nationality the office you are applying through is responsible for.  So, as you are going through Buenos Aires, you have to use the Argentinian PP.