Pindar Set, which employs 1600 people, has partnered Yell for 28 years and followed its expansion into Europe, US and India on behalf of the Yell Group.
The company was established as an external supplier to meet Yell's pre-press and typesetting requirements and has subsequently moved into its online advert processing.
According to Companies House, Pindar Set Ltd recorded a turnover of £25.3m in 2006.
Andrew Pindar, chairman of Pindar Group, said: "After a successful 28 years, we are proud of our relationship and how it has developed and we look forward to continuing to deliver excellent service to Yell in other ways through our Pindar Graphics operation."
Andrew Dalton, chief executive of Pindar, added that the deal leaves the group in a "strong position", with a turnover of £107-108m, and will remain profitable going forward.
John Condron, chief executive of the Yell Group, added: "The integration of Pindar Set within the Yell Group is the right decision for both parties, and will further enhance our working effectiveness, decision-making and the quality of service we offer to advertisers.
"I am very much looking forward to welcoming our new colleagues and to the benefits that I am confident they will bring."
Directory production operations for Yell will remain headquartered in Scarborough, and there are no planned changes to other operations in Birmingham, Bristol, Manchester and Edinburgh or overseas. There are no planned redundancies.
For more, see this week's PrintWeek.