An eagle-eyed Herald reader sent through a photograph of the sign that was up at Foodfare on McKee Avenue in Finglas.
The establishment refused to comment when contacted, but it is not the first to try and put a halt to the practice of pyjama wearing in inappropriate places, which is deemed by many people to be unhygienic.
However, the trend to wear pyjamas while going about day to day business doesn't show any sign of abating.
A Dublin youth group was forced to ban patrons wearing pyjamas during the summer with a sign stating: "Call us old fashioned, but we think young women should wear pyjamas when they go to bed, not in a youth club where there's young men and adult men."
In another instance, a children's hospital asked parents and guardians not to wear night-dresses, pyjamas or night-gowns when going into the canteen to eat breakfast, for hygiene reasons.
A leading fashionista recently branded the wearing of pyjamas in public "a disgrace".
Agency boss and former model Celia Holman Lee said: "People can wear and do what they like, but personally I think it is disgraceful. I have no idea where this trend came from, the only thing I can think of is because supermarkets are opening now all night, that maybe people just started to do their shopping in their pyjamas and it began from there."
Last year, a headmaster was so sick of parents wearing pyjamas as they bought their kids to school, he sent home a note about it with pupils.
The Belfast headmaster was fed up of seeing up to 50 pyjama-wearing women leaving children off at school.
Wearing pyjamas outdoors has become a fashion phenomena worldwide, and even celebrities have bought into it.
Madonna has hit the streets in her pyjamas several times. Michael Jackson turned up to a court appearance in 2005 dressed in pyjama bottoms, while Chris Evans wore a suit jacket over pyjama bottoms to the pub.
Psychologists, sociologists and those in the fashion industry have differing views on the reasons behind the trend. Some say it is purely fashion, others insist it is a defiant stand against social niceties, while in the minds of others, it is plain lazy.