Benllech has become Anglesey's first "no cold calling" zone.
County council trading standards and North Wales Police have launched the six-month trial.
Signs have been posted on lampposts in the town to show uninvted callers that residents do not buy goods or services from them.
A recent survey in the area showed 70% of those questioned were concerned about doorstep crime and 17% had already suffered a bad experience.
Resident Doreen Roscoe Williams, who is also the chair of the pensioners club, said she was approached by a man offering to do work on her home.
"I said 'no thank you, I don't want any work done' and closed the door on him, but when I went to the window there were about six of them trying different houses."
Mrs Williams said she lived in an area where a lot of elderly people lived and she always told them not to open their doors if they did not know who the caller was.
She added that one person from the pensioners club had suffered a night-time visit which had frightened her.
"This is worrying because the lady was in bed and they banged on her front door and woke her up.
"After getting no answer he tried the back door then started on the bedroom window."
The householder was "absolutely terrified" and could not think how to react, she added.
Mrs Williams said her experience had left her "a little shaky".
"It was the number of people outside in the cul de sac, and of course I couldn't get out to warn other people either."
Gareth Evans, the North Wales Police district inspector for Anglesey, said cold calling was generally not a big problem in the Benllech area.
"Trading standards carried out a survey and found that 20% had had a problem, but 76% were worried about the possibility of cold calling," he said.
"So it's not a huge problem but we want to make people reassured so they can live at home in peace."
Inspector Evans said the scheme was started in Benllech because of the efforts of the community beat officer who has seen other areas using it.
"Obviously we are keen to expand into other areas of Anglesey," he said.
He also urged residents to contact the police immediately if any cold callers were seen so that they could be traced and checked.