The Suez Canal permits migration of fish from the Indo-Pacific Ocean to the Mediterranean Sea. This phenomenon (Lessepsian migration) has enabled poisonous fish species to colonize the Mediterranean Sea. To report clinical tetrodotoxin poisoning after consumption of the Lessepsian immigrant fish Lagocephalus sceleratus caught on the Israeli coast of the eastern Mediterranean. Thirteen patients aged 26-70years were admitted after consuming L. sceleratus. Signs of toxicity appeared within 1h. The main manifestations included vomiting, diarrhea, headache, paraesthesias, slurred speech, muscle weakness, dyspnea, hypertension, tachycardia, respiratory arrest, seizures and coma. Treatment was supportive, including mechanical ventilation (two patients). Patients recovered within 4days. All fish were identified as L. sceleratus, a species known to contain tetrodotoxin. The diagnosis of tetrodotoxin poisoning was suggested by typical clinical manifestations together with temporal proximity to consumption of tetrodotoxin-containing fish. To the best of our knowledge, this is the first case series of tetrodotoxin poisoning reported from the eastern Mediterranean and due to L. sceleratus. Man made disruption of the ecological balance has resulted in the spread of tetrodotoxin-containing fish from the Indo-Pacific region to the Mediterranean Sea. Increased awareness is required to identify tetrodotoxin poisoning in an atypical fauna.