The Mexican materials giant wields axe only two months after buying British cement manufacturer RMC.
Cemex is to make 750 workers redundant at former RMC sites in the UK.
Cemex told analysts that it would lay off more than a tenth of the UK workforce only two months after it bought RMC for £2.3bn.
RMC has been affected by a slowdown in roadbuilding in the UK and by weaknesses in the German economy. It cut 520 jobs 18 months ago, and has cut 5,000 staff worldwide in recent years.
Cemex said that no decision had been made about the future of RMC quarries but it said that closures could not be ruled out. It said that the RMC job cuts were part of a drive to cut costs by £110 per annum by 2008.