Marijuana is the most widely used illicit substance in the world. The relation between marijuana use and epileptic seizures is still controversial. We report a case of late onset epilepsy associated with marijuana abuse, with brain magnetic resonance imaging (MRI) findings. A 44-year-old patient was admitted for 03 isolated episodes of secondary generalized tonic-clonic seizures. He had a history of 26 years regular marijuana smoking. On admission, we found a tachycardia, psychomotor slowing, asymmetric hyperreflexia, bilateral Babinski sign without weakness. Laboratory work-up showed a high level of urine of Δ-9-tétrahydroxycannabinol. Electroencephalogram was normal. Brain MRI revealed abnormal signal intensities in the right frontal lobe and basal ganglia. Seizures cessation was obtained with anti-epileptic treatment. We suggest that marijuana abuse through vascular and toxic mechanisms could explain seizures in this case.