The scoreline increases the genuine threat of relegation for Middlesbrough, who astoundingly began the season with talk of a Champions League place.
Boro are on a disastrous run and will have to pull up their socks if they are to avoid the dreaded drop.
Villa were by far the better side. They controlled midfield and were by far the more dangerous in attack.
Middlesbrough could have no complaints over the scoreline, with a hat-trick from Luke Moore and a goal by former Sunderland striker Kevin Phillips.
Middlesbrough hoped to follow up their midweek win over Sunderland with a double against their Midlands opponents but those hopes were dashed long before the interval.
Moore opened the scoring after 18 minutes following a Jlloyd Samuel pass and a flick-on by Phillips.
Six minutes later Phillips was on target with a brilliant back header from a left-wing cross by James Milner. It was a classic striker's goal with a header into the far corner past Mark Schwarzer.
Gaizka Mendieta had a shot saved by Thomas Sorensen at the other end after 26 minutes. It was Middlesbrough's first shot on target.
The visitors were controlling the game, there was a chance for Middlesbrough to pull a goal back just before the break. Stewart Downing, however, fired over the bar from a free-kick.
Middlesbrough gambled with a new strikeforce in the second half. Substitutes Yakubu and Massimo Maccarone took over from Mark Viduka and Jimmy Floyd Hasselbaink.
It was a desperate attempt by Middlesbrough to pull the game round but it had no success.
Villa went further ahead through Moore after 62 minutes and the striker completed his hat-trick two minutes later.
Moore scored at the second attempt from close range and then fired into the far corner of the net after Lee Cattermole had been dispossessed in midfield.
One angry Middlesbrough fan staged his personal act of disgust when he appeared to throw his season ticket into the Middlesbrough dugout.
With a West Brom win, Middlesbrough are now in the bottom four of the Premier League. Middlesbrough fans are unhappy with manager Steve McClaren and there was an ironic chant of "McClaren for England" by a section of disgruntled fans.
As the England coach, McClaren has featured among the candidates to take over from Sven-Goran Eriksson later this year. His prospects, however, have dipped following Middlesbrough's slide down the table.
Boro, in fact, have only won one of their last 11 league games.
Villa, on the other hand, have every reason to be happy with their performance at the Riverside Stadium. They were the best side from the word go and delighted their fans with an enterprising performance.
Moore, was substituted in the closing stages and earned a touchline hug from manager David O'Leary for his three-goal contribution.