Seizures are a very common neurological problem in small animals. Dogs and cats with seizures can be divided in to 3 main categories based on underlying cause: those with primary epilepsy, those with structural epilepsy, and those with reactive seizures. In addition some patients may be diagnosed with “idiopathic epilepsy” when they do not meet the criteria for a diagnosis of primary epilepsy, but no structural or reactive cause of seizures can be identified. This paper summarises the main clinical findings found in each of the 3 main types of seizures and suggests a standardised approach to diagnosis based on the patient’s signalment and neurologic examination findings.