Some 50% of beds - or more - are in homes rated as needing improvement or inadequate in six local authority areas. Thats according to a report that analysed data by the Care Quality Commission.
In Manchester three in five beds (58%) are in below-standard homes.
However there's better news in Lancashire.
Nine in 10 care home beds are in homes rated as good or outstanding in Blackburn with Darwen.
The report by consumer group Which? said the analysis highlighted the "huge" regional variation in the provision of quality local care across the country.
The watchdog warned the situation could rapidly worsen as demand starts to outstrip supply in an increasing number of local areas.