Real Madrid center-back Ramos earned a 177th appearance for Spain in Saturday's Nations League match against Switzerland, having pulled level with Buffon when coming off the bench against the Netherlands on Wednesday.
It means Ramos, a World Cup winner with Spain, is now just eight short of the overall record held by Egypt's Ahmed Hassan.
As well as his triumph in South Africa in 2010, Ramos has won two European Championships with Spain and scored 23 goals for his country – putting him joint eighth on the list with Alfredo Di Stefano.
Indeed, no player has won more games for his country than Ramos (129 prior to kick-off against Switzerland).
Coincidentally, Ramos has played against Italy 10 times – more than any other nation – and faced Buffon on each occasion, winning four of those matches while losing just one.
The 34-year-old has played in 17 World Cup games and 15 in the European Championship, while 97 of his caps came under the leadership of Vicente Del Bosque, winning 76.2 percent of those matches under the ex-Madrid coach.
Ramos' international career began in 2005 against Chile and by the age of 26 he had already racked up a century of appearances.
Buffon's last Italy outing came against Argentina in March 2018, some 7,450 days after making his Azzurri bow against Russia in October 1997.
The Juventus great, also a World Cup winner, kept 68 sheets and clocked up 15,243 minutes played for his country.