August.One loses the brief after three years handling corporate PR for the group.
According to Microsoft Asia-Pacific group manager of corporate communications Olivier Richard, the review was prompted in part by an operational reshuffle.
He said the review reflected 'the growing importance of the Asia-Pacific region for Microsoft. We have to organise in a way that reflects this'.
On Edelman's appointment, he added: 'Edelman has more bandwidth, more offices and gives us more access and responsiveness to answer media requests across the region in a consistent way.'
The account will be run from Hong Kong and handled by Edelman client relationship manager Alannah Goss. Edelman Asia-Pacific president Alan Vandermolen said a significant proportion of work would also originate from the agency's Singapore office.
The account brief remains focused on key regional media and analyst relations.
Microsoft confirmed 14 regional subsidiaries will continue to use local PR support.
August.One Hong Kong managing director Deepa Swaminathan said the consultancy will continue to handle 'positioning and messaging' for Microsoft's Mobile Services Division and games console X-Box within the region.
News of Edelman's win comes as Microsoft reaches the top of Delahaye Medialink's third annual US media reputation index survey, up four places since last year.
The media analysis, developed with the Reputation Institute, ranks the Hoover 100 - the largest US companies - according to how they were portrayed by the media in 2002.
Microsoft's new products, such as the X-Box, and its success in overcoming legal woes were cited as reasons for its rise to the top.
Wal-Mart moved up four places to take second place behind Microsoft, followed by Walt Disney, General Motors and IBM.