The 6ft 3ins defender has 17 caps and played for his country in the 2006 World Cup qualification campaign.
Gyepes, who will compete for the centre-back positions with Roger Johnson and club captain Darren Purse, said: "I have played at this level before with Wolves and am very excited by this new challenge.
"Cardiff is a beautiful city with a superb new stadium and I want to be part of that future.
"It is a big challenge for me and I will always give Cardiff 100 per cent commitment. I look forward to helping this club have a successful season."
Cardiff chairman Peter Ridsdale said: "We're delighted to have signed him. Before he was injured at Wolves he had a bright future at this level."
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