The US Department of Justice has cleared Adobe Systems' proposed £2bn acquisition of Macromedia.
Pending approval in Europe, Adobe said it expected the deal to close later this autumn.
Adobe announced the takeover in April and received shareholder approval in August.
The company’s PDF (portable document format) system and Adobe Reader and Acrobat products lead the field in electronic document handling, and Macromedia's Flash player is estimated to be on more than 90% of the world’s internet-enabled computers.
Macromedia’s Dreamweaver also has a big slice of the website development market. The combined company is seen as an important counterweight to Microsoft in web and graphics development.
Microsoft recently announced that its forthcoming Office 12 collaboration suite will support Adobe's PDF system.