The Canadian Government does not issue Nulla Osta, which is the certificate of non impediment you need to have in order to get married in Italy, however they do issue a declaration containing the relevant information which is accepted by the Italian authorities.
To obtain it a Canadian Citizen must first complete and swear an affidavit to the effect that there is no impediment to the proposed marriage.
The affidavit can be sworn in Canada, or you could go in person to the Canadian Embassy in Rome, in this case you will only need to book an appointment by contacting them by e-mail or fax
You should bring the following documents with you:
• Valid Canadian passport
• Proof of Canadian citizenship (Canadian birth certificate or Certificate of Canadian Citizenship) .If you were born in Québec: Only birth certificates issued on or after January 1, 1994, by “Le Directeur de l’état civil” in the province of Québec are accepted
• Complete details of the future spouse (full name, date and place of birth, residence, father's name and mother's maiden name)
• Final divorce decree or death certificate of previous spouse (if divorced or widowed)
• Parents' consent (if the person is under marriageable age)
Please note that, a woman whose previous marriage was terminated within the last 300 days had to obtain a waiver from the competent Procura della Repubblica" in Italy (Court) in order to marry in Italy.
The declaration issued by the Embassy or Consulate General must then be presented to the competent "Prefettura Ufficio Legalizzazioni" to be authenticated. We can help you out with this.