The company restored Internet access for its 200,000 employees on 24 September after the Nimda worm hit early the previous week.
IT personnel suspended access to the Web and the company Intranet on 18 September after determining Nimda was to blame for unusual amounts of network traffic, said spokesman Jeremy Cohen.
"When the IT personnel saw the unusual increase in network activity, they shut down parts on the network to limit the spread [of Nimda]. Internet access was restored on Monday," he said.
Philips is in the process of assessing the impact of Nimda across the 60 or more countries in which it has operations.
The company had back-ups in place for Web-based electronic business systems, according to Cohen.
"We have maintained legacy IT systems - those we used before we switched to another e-commerce solution. Initial indications are that Nimda only had a limited effect on IT systems and business," he said.
Nimda exploits known vulnerabilities in Microsoft's Outlook e-mail clients, Internet Explorer and Internet Information Server Web server software to spread via e-mail, Web sites and across shared disks on networks.
Philips has yet to determine how the virus got into its systems, but the relevant software is being updated.
"When I logged on this morning I noticed a number of different updates being installed," said Cohen. "IT staff have been sending through news on the situation, but no new usage guidelines," he said.