The charity has since apologised to Ranjini Renvoize for what it describes as "poor supporter care" after the two letters she sent informing the charity of her husband's death went unnoticed.
Paul Mullins, supporter relations manager at Oxfam, said he was confident the error was an isolated incident. He said the charity's system had failed because one of Renvoize's letters did not arrive, and because staff had not followed correct procedures when the second letter was received.
"I am comfortable the procedures are there, and we don't have a gaping hole in our system," he said. "Inevitably, sometimes, things go wrong."
Meanwhile, Guardian News and Media, the company that owns the Guardian and Observer newspapers, has joined a non-profit data-sharing consortium that aims to stop direct mail being sent to dead people. Other members of the Stop Dead Consortium include Age Concern and Help the Aged. The consortium pools resources by identifying people on their customer databases who have died, then sharing their names with other members to update their mailing lists.