Defence Secretary Michael Fallon said Saudi Arabia had confirmed munitions bought from the UK in the 1980s had been dropped.
Since 2010 it has been illegal under British law to supply the bombs, which put civilians at risk by releasing small bomblets over a wide area.
Labour said it was "deeply worrying" cluster bomb use had been confirmed.
The UK is supporting the Saudi-led coalition which is fighting the Houthi rebel movement in Yemen.
In a statement to MPs, Mr Fallon said the UK had not supplied any cluster bombs to Saudi Arabia since 1989.
But he added that Saudi investigations had concluded that some UK-made cluster bombs had been dropped.
The BL-755 bombs will no longer be used by the coalition, he added.
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