The Nigerian has been linked with a move away from Vicarage Road throughout the transfer window so far, and speculation is increasing about his future.
The Baggies were keen on landing the hitman last summer, and have now renewed their interest in Ighalo, who is also wanted by teams in the Chinese Super League.
Baggies interested in Ighalo
West Brom boss Tony Pulis has made it clear that he would be interested in bringing the 27-year-old forward to the Hawthorns, and he has made him a top priority this January.
The Watford Observer reported that talks between the two clubs and player are at an "early stage" at the moment and no deal for the player will be struck imminently.
Any move for the player, who has been out of form so far this season could happen at the end of the month, meaning the Hornets will be sitting tight to see if one of last seasons bright aspects will stay or leave.
Forward out of form this season
Ighalo has only managed to record two goals so far this season, and compared to his blistering form last campaign, the forward has had a disappointing season so far.
"I would like that, when we have the game which we have in a couple of days," he told the Observer. "We speak as little as possible about the transfer market. In this moment Odion Ighalo is a player that will travel with the team for this weekend."
Last summer, Ighalo turned down a big-money move to China with Shanghai SIPG, but if the striker is set to move away from Watford, they would need to bring in a replacement.