Federal Prosecutor Giuseppe Chine opened the investigation after 42-year-old Buffon was overheard using a blasphemous expression when addressing team-mate Manolo Portanova during Juventus's 4-0 win over Parma last weekend.
The incident was not reported because Buffon was not on camera at the time, but there was an audio recording.
"The investigation will serve to clarify through the possibility of listening to the person concerned," an FIGC statement read.
Since 2010, the Italian FA has taken disciplinary action against several players and coaches heard disrespecting "God" or "the sacred".
Former Italy captain Buffon, the oldest player in the league and holder of the record for Serie A appearances with 653, has in the past been forced to apologise for uttering the word "Dio" (God), although he once claimed he had said "Zio" (uncle).
Roma's Bryan Cristante was given a one-match ban for blasphemy earlier this month for swearing after he conceded an own goal in a league game earlier this month.