L'Orιal will move work abroad from Talbot Green, where it has been for 35 years
About 200 jobs are set to be lost at the cosmetics firm L'Orιal in the south Wales valleys.
Currently some 260 people work at the factory at Talbot Green, near Llantrisant in Rhondda Cynon Taf.
The proposal is for the factory to be sold to another French cosmetics and pharmaceutical group, Fareva.
It is believed they will keep 60 jobs producing L'Orιal hair products for the UK market. The rest of the work is being transferred abroad.
A spokesperson for L'Orιal said the decision had nothing to do with the global downturn.
She said the main reason was because of transport costs associated with importing 70% of its raw materials from abroad and then sending most of the end product abroad as well.
The announcement is subject to the usual three month consultation.
The factory produces shampoos, conditioners and styling products for L'Orιal's UK market as well as for Europe and some markets further overseas.
A L'Orιal spokesman said Fareva had "expressed its intention to develop the site significantly over the next few years" rebuilding it to current job levels.
The company, which has been at Talbot Green since 1973, said those employees whose jobs become redundant at the plant will be offered help in finding new job opportunities within the L'Orιal group or elsewhere.
One worker at the plant told the BBC he was angry and upset by the announcement and said the mood at this morning's mass meeting with management was "very sombre".
He said workers had met all the targets that had been set for them and sometimes exceeded them.
A company spokesman said: "We will work closely with the trade union and elected employee representatives and will do everything possible to keep those involved fully informed of developments during the consultation process."
L'Oreal produces 25 worldwide brands, with sales worth 17bn euros last year. Its chairman and former chief executive Sir Lindsay-Owen Jones has Welsh family connections.
Economy Minister Ieuan Wyn Jones said: "This is very disappointing news.
"L'Orιal is a long established employer in south Wales and many of the people affected by this announcement have worked for the company for a considerable period of time," Mr Jones added.
"We will do everything within our power to protect these jobs and a meeting has been arranged early next week with senior representatives from the company to discuss this announcement."
Russell Roberts, leader of Rhondda Cynon Taf council, said: "There is obviously never a good time to suffer such a blow to the local economy but it goes without saying that when people are understandably worried about the current economic climate, this will be devastating for the staff who are affected.
"We will be making strong representations to L'Orιal management and working with the trade unions and colleagues in the assembly government to make the case for reconsideration."