The 42-year-old was arrested at an address in Leeds last night on suspicion of arson.
It follows fires started at the front doors of the Jamia Masjid Abu Huraira Mosque in Hardy Street, Beeston, and the Guru Nanak Nishkam Sewak Jatha Gurdwara, in Lady Pit Lane, in the early hours of yesterday.
The man remains in police custody today as enquiries continue.
Detective Inspector Richard Holmes, of Leeds District CID, said: “We are continuing to progress the investigation and the man in custody will be interviewed about the incidents today.
“We are continuing to carry out extensive enquiries, including a detailed trawl of CCTV in the areas surrounding both incidents."
Det Insp Holmes said: “We are continuing to liaise with our colleagues in the local neighbourhood policing team who are maintaining an increased presence in the area and having regular contact with key representatives from the communities affected to keep them updated and to reassure the wider community.”
Anyone with information is asked to contact Leeds District CID via 101 quoting crime reference 1318270739 or call the independent charity Crimestoppers anonymously on 0800 555 111.