Saudi Arabia is to change the start of its two-day weekend from Thursday to Friday, official sources say.
The change will bring it into line with other countries in the region and help co-ordinate business and banking days.
A similar proposal in 2007 was rejected, but the Saudi business community has been lobbying for the change so that it can harmonise its activities with regional commercial hubs, such as Dubai.
A royal decree takes effect this week.
After Oman switched to a Friday-Saturday weekend last month, Saudi Arabia was the only country left among the six-member Gulf Co-operation Council to persist with the old format.
A statement carried by the the national Saudi news agency SPA said the change, decreed by King Abdullah, was "for the sake of putting an end to the negative effects and the lost economic opportunities consistently associated with variation based on work days between local departments, ministries and institutions and the regional and international counterparts."
It will mean that Saudi businesses will now have four working days overlapping with Western and regional businesses rather than three, making it easier to trade.
Friday remains a holiday in Muslim countries because it is a holy day set aside for communal prayer.