Seizures are a frequent neurologic complication of cancer. Seizures may develop as a consequence of direct extension of cancer into the brain or surrounding meninges, an underlying metabolic imbalance from treatment or the tumor, or the neurotoxic effects of cancer therapy. Emergency treatment is essential for status epilepticus and seizures that occur frequently to prevent permanent neurologic sequelae. In all cases, a diagnostic evaluation is required to discover the underlying cause of the seizures. Often, an easily reversible process will be uncovered, and the complete resolution of the seizure disorder can occur. In other circumstances, determining the cause of the seizure may allow early diagnosis and treatment of brain lesions or may disclose neurotoxicity, thereby modifying future treatment. This article reviews the causes, diagnostic evaluation, and treatment of seizures in adult patients with cancer, providing an overview of the medical and nursing aspects of patient management.