The Institute awarded the Cambridge team with the prestigious title at its annual conference earlier this month.
The awards judging panel were looking for organisations to demonstrate they were raising standards of service to achieve high levels of performance, customer satisfaction and effective administrative procedures in all aspects of welfare benefits.
After the council team was shortlisted for the award in June, an inspection team visited Cambridge in August to see their day-to-day work, and speak with partners and colleagues from across the council.
Cllr Richard Robertson, Executive Councillor for Finance and Resources, said: “Winning this award is a fantastic achievement for the Benefits team, and one that is well-deserved, as they really are a group of people motivated to do their best for customers.
“Good teamwork and a desire to do their best for those in need of support are core to the way they operate, and this award is national recognition of their achievements.
“The team works hard to support those in need of help, and currently awards £44million a year to people living in the city by way of housing benefit and council tax reduction.”
The Institute of Revenues Rating and Valuation (IRRV) is the professional body for those working in the field of revenues, benefits and valuation in the United Kingdom. It is the largest professional association in the field with over 3,500 members, offers a range of qualifications covering its professional fields, and is a nationally-approved body for its vocational and examination-based qualifications.