The Barcelona star admits the goalkeeper's exit will be emotional and attempted to play down the recent controversy surrounding Lionel Messi
The goalkeeper, who has been a member of the first-team squad at Camp Nou for 12 seasons, announced in May that he will not be extending his contract when it expires in 2014.
Iniesta says his team-mate's departure will come as a blow to a squad he feels is progressing well under new coach Gerardo Martino.
“There is no doubt I will cry when Valdes leaves,” the 29-year-old told reporters.
“We just have to hope we can win trophies this season so that he enjoys a good departure.
“The squad’s connection with Tata has been great from the start. He is a good person and a real football man - he knows exactly how players feel."
The Spain international, who has recently signed a new contract to keep him at Barcelona until 2018, has said he is now expecting to see out the remainder of his playing career with the club.
Iniesta also attempted to play down recent critical remarks made by Lionel Messi about vice-president Javier Faus and backed the Argentine to win the Ballon d’Or in January.
He said to La Sexta: “Messi is a fundamental player for both me and the club. Sometimes things are said without thinking or without meaning to cause hurt.
“I would love for him to win the Ballon d’Or. Everyone in the squad would feel like part of the success.
“I went to my contract signing with my parents and my daughter. I thought about a lot and I was the proudest person in the world. My dream is to end my career at Barca.”
Barcelona return to match action against Elche on January 5 before they meet Getafe in the first leg of their Copa del Rey tie three days later.