In this prospective study, eleven Finnish Spitz dogs with focal idiopathic epilepsy (IE) and six control dogs were examined using electroencephalography (EEG) and 2-deoxy-2-[18F] fluoro-d-glucose positron emission tomography (FDG-PET), with epileptic dogs being evaluated during the interictal period. Three independent observers, blinded to the dogs’ clinical status, reported FDG-PET uptake abnormalities in 9/11 epileptic (82%), and 4/8 healthy dogs (50%) with the occipital cortex being the most commonly area affected in epileptic dogs. This suggests FDG-PET is a useful diagnostic test for dogs with suspected IE. Visual and semiquantitative analyses of FDG-PET scans provided complementary information. Results also suggested that epileptogenesis can occur in multiple brain regions in Finnish Spitz dogs with IE.