The 22-year-old Arsenal goalkeeper, who made eight appearances for the Millers last season and was vital to helping his temporary club attain Championship survival, will head to Molineux for the rest of the 2015/16 campaign and challenge Carl Ikeme for the number one jersey.
Millers boss Steve Evans was desperate for Martinez to return to the New York Stadium over the summer following his exploits last season and put the Argentinian in a two-man shortlist along with Derby man Kelle Roos.
Despite his interest in Martinez, Evans instead chose Dutchman Roos as he could get his deal over the line first.
Roos did not do much to endear himself to the Millers faithful against the MK Dons on Saturday, where he put in a particularly shaky performance on his Football League debut and conceded four goals, and the news of Martinez's move will come as a blow to those who harboured hopes of a New York return.
Evans was full of praise for his 30th signing of last season and said in May: "I think he's been great for us. We're going to be watch Emi on Match of the Day in six to eight months and then for a number of years as Arsenal's number one.Jackett has also confirmed that Wolves have a verbal agreement with @Arsenal for the loan of Emiliano MartÃnez. Hopefully completed today.
— Wolves (@OfficialWolves) August 10, 2015
"I know for a fact he has a couple of clubs in the top division in Spain wanting to take him on season-long loans. It wouldn't surprise me then if we're not seeing him in the Premier League we'll be seeing him against Barcelona and Real Madrid. That's how well he's regarded."
