London's busiest jail is "overrun with cockroaches" and has an "unusually high" number of assault allegations against staff, a report has said.
The report said prisoners "lacked basic requirements"
The Chief Inspector of Prisons, Anne Owers, also accused Pentonville of "institutional disrespect" of inmates.
The Prison Service said Pentonville's governor was taking a robust stance in dealing with prisoner complaints.
Another report has concluded Peterhead prison inmates are living in the worst conditions of any in Scotland.
The jail housing 300 sex offenders was said to be Scotland's only prison where slopping out was still usual practice.
Ms Owers' report on Pentonville was published following an unannounced inspection in June.
It revealed that 43% of prisoners - down from 64% in 2005 - said staff treated them with respect.
Allegations of victimisation rose from 29% to 40% over the same period.
Of 12 main recommendations made in a 2005 report, seven had not been achieved and another four had only partially been met.
This year's inspection also found 55% of prisoners said they felt unsafe and 42% claimed it was easy to obtain drugs.
Ms Owers' report also said inmates at the prison in Islington, north London, lacked basic requirements such as pillows, while at times there was not enough food.
"They found some improvements: prisoners were out of their cells more than they had been," Ms Owers told BBC Radio 4's Today programme.
"But we did find a deterioration in relationships with staff. I think what we did find was that the new management team had inherited a prison with virtually no systems for making sure that prisoners got the basics they needed, and for managing and monitoring the behaviour of some staff. "
She said her findings highlighted the scale of problems in "overcrowded and pressurised" local prisons.
"What they were faced with is the rising prison population, the fact that they've no headroom, the fact they've got a hundred prisoners sometimes coming in a day.
"It's a very difficult environment in an old building in which to try to make the kind of changes Pentonville needs," Ms Owers said.
Pentonville was said to be "overrun with cockroaches and vermin" caused by leftover meals and open flour sacks in the kitchen.
The Prison Service said Pentonville had been operating under "significant pressure" but had recently strengthened its senior management team.
"Pentonville now has a pest control programme in place," a spokeswoman said.
Food occasionally runs out due to poor portion control but no prisoner goes without a meal, she added.
Juliet Lyon, of the Prison Reform Trust, called on the home secretary to consider closing Pentonville as it was "not fit for purpose".
She added: "The Pentonville of this report would be more in place in Hogarth's Gin Lane than Islington today."
Richard, a former Pentonville inmate whose nine-month sentence for grievous bodily harm ended in 2000, recalled seeing cockroaches in the prison.
Referring to the conduct of prison guards, he said: "Everybody feared them".
The Scottish inspectorate's report on Peterhead noted there had still been no announcement on its future following a 2005 consultation.
Dr Andrew McLellan also warned sending Peterhead's sex offender inmates back into the community without preparatory supervision in the community "is not a good recipe for safety".
The future of Peterhead Prison remains unclear
However, he said relationships between staff and prisoners were good.
Positives also included the fact that drug use was very limited and that food and visiting arrangements consistently received high marks from prisoners.
The report said a large number of complaints were made by a small number of prisoners.
Members of the Scottish Parliament have been told slopping out could cost nearly £60m in legal claims following a test case which found the practice was a breach of prisoners' human rights.
The Scottish Prison Service say ending slopping out at Peterhead is not a cost-effective option given the age and structure of the Victorian building.