Rizwan Ahmed was letting a three-storey, nine-bedroom residence on Fulham Road - that was occupied by at least five tenants - without the required certification and received a £20,000 penalty as a result.
It was also found that he had breached five rules of the HMO by failing to maintain fire doors, wall and ceiling plaster and fire alarm systems.
A spokesman for Hammersmith and Fulham Council noted that Mr Ahmeds tenants had been living in poor conditions.
"This should be a warning to all landlords that the council takes HMO licensing and management regulations seriously," he remarked.
Those interested in finding out more about the HMO can do so at the Office of Public Sector website, as well as the Department for Communities and Local Government.