Etuhu is 21 and the younger brother of Fulham player Dickson Etuhu. He signed on Saturday in time to be included in Cardiff's squad for the game against Bristol City.
"We are really pleased to get Kelvin," Dave Jones told the official webiste.
"He's a Premier League player... it looked like he was going to Wolves but there was a hitch and we stepped in.
"He's a big, pacey lad who will give us options across the front line."
Jones was looking for cover after Ross McCormack was injured at Blackpool a week ago.
Etuhu is available for all competitions unless City are drawn against Man City in a cup match.
City sign Man City forward on season long loan
