Mr Robinson has not been at a meeting of Welshpool Town Council since the summer.
In a statement released today, the council said that it was confirming the retirement of Mr Robinson from October 1 after 13 years service to the community.
Welshpool Mayor Steve Kaye said: "The council is grateful for the loyal service given by Robert over the years and wishes him all the best for the future in his retirement."
Mr Robinson said: "I have enjoyed working with the councillors and staff of Welshpool Town Council and wish the council all the best as they progress into a new era."
He became the town clerk in July 2006, when he took over the role from Ken Fletcher.
In September 2018, it was announced that he would reduce his commitment to the role, and was expected to retire in 2020 or 2021.
The council says it is now looking towards appointing a successor.