Solicitor Ryan Hermann, who has an office backing onto Abington Place, has had to deal with bikes, fridges, televisions, rotten food and human waste, which has all been dumped outside of his premises in a shared car park.
Mr Herrmann, of Herrmann Lawyers, has spent thousands of pounds to remove the rubbish in the area, which includes private skip hire, CCTV and painters to clear graffiti.
Ryan said: "Put yourself in my clients' shoes, what is your first impression of my practice? I think it's unacceptable.
"I have the possibility to move into my other office at the Drapery, but that shouldn't be my choice. I shouldn't have to move my business because of fly tipping."
The car park is also a hotspot for homeless people who have been found asleep in St Edmunds House toilets.
Peter Short of NSL, based in St Edmunds Road, said: "We've had to pay £200 to put new locks on the doors as we've found at least two homeless people asleep in the toilet, which has caused many female workers to feel unsafe.
"We've had to move our bins to the side of the building because of the rat infestation.
"I often see rats wriggling through the bin bags. I think they feed off the fat which is distributed by kebab houses and rotten meat which the supermarkets chuck away."
Some of the affected land is owned privately, however some is public land and therefore the responsibility of Northampton Borough Council.
Councillor Alan Bottwood, said, “We regularly work with the community and businesses to tackle their concerns of fly-tipping around the town.
"As part of this we introduced fixed penalties for fly tipping in May, with the hope of deterring potential offenders and thus reducing the number of cases occurring. Although it is still early days to say how effective these penalties have been, they have resulted in a number of investigations taking place.
"We urge for the public to get in touch and report any incidences of fly tipping, when they happen, to assist our work in this area further.”