Epilepsy is an increasingly recognized comorbidity in Alzheimer's disease (AD). First described as generalized in dementia patients, epileptic AD patients are nowadays fully described in earlier stages of the disease (with mild or subjective cognitive impairment). At such early stages, patients may present not only with generalized seizures, but also with focal seizures (commonly localized in the frontal or temporal lobe). Thus, partial or generalized epilepsy is part of the semiological spectrum of AD that should be borne in mind at all stages of disease to ensure early identification and prevent the risk of repeated seizures (such as accidents, injury, progression of cognitive impairment). This review of the available (and still growing) literature shows that there are already sufficient data to inform physicians on seizure semiology, and on the diagnostic value of electroencephalography and brain imaging. Taken together, these tools can help to rapidly identify epilepsy in AD patients. Nevertheless, epilepsy diagnosis can be challenging, and test medication is sometimes necessary. Some cerebrospinal fluid biomarkers (or their ratios) may also prove to be good predictors of seizures in AD, but further studies are needed. Epilepsy in AD patients is frequently pharmacosensitive, and a good response can be obtained with standard doses of antiepileptic drugs. For all these reasons and based on our review of the literature, it appears that, at present, the diagnosis of epilepsy in AD is not only possible at any stage of the disease, but also to be recommended to improve the patient's prognosis.