A BSTRACT Introduction: Seizures are one of the most common neurological emergencies encountered in both urban and rural India. There is only limited research work on the etiology of new-onset seizures in adult patients of different age groups presenting to the emergency department, especially from the Indian sub-continent. A new-onset seizure can be the first presentation of stroke, or it may be a symptom of brain infections, metabolic abnormality, brain tumor, systemic disease, or an early phase of epilepsy, which needs scrutiny and appropriate management. A dedicated study of the underlying etiology of new-onset seizures among different age groups and their incidence and prevalence can help in the prognostication and clinical management of these patients. Materials and Methods: This was a prospective observational cross-sectional study conducted in the Emergency Medical Out-patient Department and emergency medical ward of the Post-graduate Institute of medical education and research, Chandigarh. Results: In our research, males out-numbered females. The most common seizure type recorded in our study was generalized tonic-clonic. In the younger age group between 13 and 35 years, infective etiologies were dominant. In the middle age group between 36 and 55 years, cerebrovascular accidents were the dominant etiology, followed by infective causes and metabolic causes. In the older age group above 55 years, the most dominating etiology found was cerebrovascular accident. Almost 72% had abnormal brain imaging. The most common abnormality found was ischemic infarcts. The second most common abnormality detected was a meningeal enhancement. A small percentage of patients had an intra-cranial bleed, and a very small percentage had a subarachnoid hemorrhage. Conclusions: In younger patients, infections such as tubercular and pyogenic meningitis and cerebral malaria are the most common causes of new-onset seizures, followed by malignancy and metabolic causes, in descending order. In the middle age group, stroke is the most common etiology, followed by central nervous system (CNS) infections and metabolic causes, in descending order. In elderly patients, stroke is the leading etiology for new-onset seizures. Physicians working in rural and remote areas routinely face challenges in managing patients with new-onset seizures. Knowledge of different etiologies in different age groups will equip them to make informed decisions regarding investigations and treatment of patients with new-onset seizures. It also encourages them to aggressively search for CNS infections, especially in younger patients.