Market Square customers will be able to shop without being subject to nuisance and anti-social behavior with the addition of two police officers.
The temporary officers will be paid for by Northampton Borough Council and come after sustained complaints by market traders.
They are fed up with cannabis smokers and drinkers hanging around the empty stalls and intimidating shoppers.
Fruit and vegetables seller Eamonn Fitzpatrick said: "They're gangs of kids who are on legal highs, and you can smell cannabis from them constantly.
"We feel intimidated and customers feel intimidated too.
"They're bringing the place down."
The officers will patrol the Market Square and surrounding area for six weeks from November 19, covering the busy Christmas shopping period. Their beat will be the town centre inner ring road, with Broad Street as its western boundary and York Road as its eastern boundary.
A similar initiative was tried in the summer when the borough council funded overtime for temporary police officers in the town centre at a cost of £19,700.
The officers disrupted drug dealing activity, made 207 seizures of alcohol and 11 arrests, and took enforcement action against 11 people for alcohol and drug-related incidents or anti-social behaviour.
Councillor Anna King (Con, Phippsville), cabinet member for community safety, added: “We also have a dedicated market team and town centre warden, and the Council’s waste partner Veolia cleans the market square on a daily basis.”
The new officers will be able to enforce the Town Centre Public Space Protection Order. It prohibits urinating and defecating in public and the public consumption of intoxicating substances.