Opioids are commonly used and abused substance worldwide. Opioid withdrawal may manifest as severe muscle cramps, diarrhea, rhinorrhea, lacrimation, piloerection, yawning, and fever. Here, we report a 32 year old man with heroin dependence, presented with new onset generalized tonic-clonic seizure following heroin withdrawal. Seizure is a life-threating condition and rare phenomenon in opioid withdrawal therefore, reporting of this case is important. It may help clinician to be aware and consider seizure as a part of opioid withdrawal.