Professor George Salmond's unusual pastime appeared in the 1998 edition of Who's Who alongside his other hobbies, which included: driving sports cars, good wine, malt whisky and comedy.
The head of a homeless charity in Cambridge said she was "horrified" that such a senior and learned academic could make such a comment and "very surprised" Who's Who had allowed it to be published.
The professor of molecular and microbiology who has also worked at Strathclyde, Edinburgh, Warwick and Kent, was unavailable for comment.
A spokeswoman for Who's Who said the entry had been written by Professor Salmond and editors had thought it suitable for publication. A spokeswoman for Cambridge University "could not comment".
Ruth Wyner, director of the charity Winter Comfort, said the comment would do nothing to help those working to improve the plight of the homeless. "I am absolutely horrified. I cannot believe Who's Who can print things like that," she said. "It is really ghastly. It does not sound like the comment of an intelligent person."
She added: "We get people from all sorts of backgrounds who find themselves on the streets, including students. I hope none of Professor Salmond's family ever find themselves on the streets.
Police said there were problems with aggressive begging last year.
Chief Superintendent Keith Hoddy, the officer in charge of Cambridge and its outlying areas, said: "There has been a problem in the past but I would say it is less than it has been now."Reuse content