The singer and former soap star was brought on board, alongside Ricky Wilson of Kaiser Chiefs, as part of a revamp of the Saturday night talent show at the start of this year's third season.
Her presence generated lots of publicity, but last weekend's live final, won by Jermain Jackman, was watched by fewer than 7 million viewers, down on both the previous two series.
Minogue said she would not return owing to touring commitments following the release of her latest album, Kiss Me Once.
"I'm sad to say that, due to the timing of my European tour, I won't be back for season four," she said.
"I absolutely loved my time on the show, and I'll miss all of the incredible people who were a part of my experience … and wish continued success to everyone at The Voice!"
The BBC has commissioned The Voice for a fourth and fifth series, despite the failure of any of its winners to make much impact on the charts.
The only female judge on the show – the BBC prefers to call them "coaches" – Minogue's exit comes after the BBC's director of television, Danny Cohen, said it was unacceptable to have a panel show without a female panellist.
Minogue, who replaced Jessie J, said at the series launch this year: "I think it works really well, one girl and the three guys … Maybe it would be interesting to have three women and one guy."
Her introduction was intended to make the show warmer and friendlier, although there have been complaints that the judges were not critical enough.
It remains to be seen if all the other three judges – Wilson and the original pairing of, will.i.am and Sir Tom Jones – will return for a fourth series.
The BBC said discussions about the series four line-up were "ongoing" with an announcement expected "in due course".
Moira Ross, executive producer at Wall to Wall, the independent producer that makes The Voice, said: "Kylie has brought her own very special magic to The Voice UK and we have loved having her on the show. We wish her well for her tour and hope to welcome her back in the future."
The show, a rival to Simon Cowell's long-running ITV shows Britain's Got Talent and The X Factor, has proved controversial because it is hugely expensive and was a bought-in format, rather than created by the BBC in-house.
Despite never breaking through to achieve the stellar ratings enjoyed by its BBC1 stablemate, Strictly Come Dancing, it remains a central part of the BBC's weekend entertainment line-up.
Minogue tweeted on Friday: "Due to timing of my tour I won't be back next season for The Voice UK. Thanks to all who supported! Hope to see you on my KMO tour!"
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