"I am pleased we've got something sorted now," Hulse told Leeds' official website. "I've had a brilliant couple of months here. It was nice to get back into playing again at a fantastic club."
Hulse said he will be expecting to get "at least 20 goals" next season, adding: "I am looking forward to the challenge next year and I think we have got a hell of a chance of promotion."
Hulse joined Albion in an £800k switch from Crewe almost two years ago and impressed in his first season. But, plagued by a stomach injury, he slipped behind Kevin Campbell, Rob Earnshaw, Kanu and Geoff Horsfield in the Baggies' pecking order this term.
He made just seven substitute appearances before joining Leeds on loan.
Manager Bryan Robson said: "I thought Rob was at the stage where he needed first-team football and I couldn't guarantee him that. He was behind the other four forwards we've got which is why I allowed him to go out on loan.
"He's done a terrific job at Leeds and we wish him all the best."