During April and June 2008, we investigated three outbreaks of marine puffer fish intoxication in three districts of Bangladesh (Narshingdi, Natore, and Dhaka). We also explored trade of marine puffer fish in Cox's Bazaar, a coastal area of the country. We identified 95 people who had consumed puffer fish; 63 (66%) developed toxicity characterized by tingling sensation in the body, perioral numbness, dizziness, and weakness, 14 of them died. All three outbreaks were caused by consumption of large (0.2-1.5 kg) marine puffer fish, sold in communities where people were unfamiliar with the marine variety of the fish and its toxicity. Coastal fishermen reported that some local businessmen distributed the fresh fish to non-coastal parts of the country, where people were unfamiliar with the larger variety, to make a quick profit. Lack of knowledge about marine puffer toxicity contributed to the outbreaks. Health communication campaigns will enhance people's knowledge and may prevent future outbreaks.