Background: Epilepsy is a group of disorders characterized by recurrent unprovoked seizures. It is recognized as one of the most common neurological diseases affecting different age groups. Objectives: This study aimed to determine the causes of secondary epilepsy in patients with epilepsy at Mashhad hospitals in 2011 -2012. Patients and Methods:In this cross-sectional, descriptive study, 300 participants were selected via available sampling from patients with epilepsy referred to hospitals affiliated to Islamic Azad University of Mashhad. Diagnosis of epilepsy was based on the criteria of the International League Against Epilepsy. Patients' demographic and medical profile questionnaires were completed, using clinical examinations, electroencephalography (EEG) and brain imaging. Results: In this study, 54% and 46% of participants were male and female, respectively (mean age = 31.5 ± 15.3 years). Head trauma was the most common cause of secondary epilepsy, observed in 26% of patients. Brain tumor (9.7%), stroke (9.3%), brain infection (8.3%), metabolic disease (3.3%) and birth trauma or congenital anomalies (2.3%) were other causes. Findings of the last performed EEG were normal and abnormal in 49% and 51% of participants, respectively. Moreover, results of brain imaging were normal in 85.3% and abnormal in 14.7% of subjects. Conclusions: This study evaluated the causes of secondary epilepsy. Our findings showed that 45.3% of the subjects had secondary epilepsy. Some patients presented with multiple conditions and there was more than one cause of secondary epilepsy in these cases. This study showed that the average age of patients with previous history of stroke was higher than that of other participants. However, previous history of stroke and head trauma mostly observed in males.