The toxicity of two species of puffer fish, Takifugu pardalis and T. niphobles, collected from the coastal regions of Korea was determined using a mouse bioassay. In T. pardalis collected at Tongyeong, the proportion of toxic specimens containing exceeded 90% for the skin, fins, liver, intestine, ovary, and gallbladder, 11.1% for the testis, and 6.9% for the muscle. In each of the organs, the highest toxin levels were several tens (14-39) of mouse units (MU) per gram in the muscle, testis, and eyeball, but thousands (1,444-5,755) of MU per gram in the skin, liver, intestine, ovary, and gallbladder. The organs of T. pardalis exhibited remarkable variation in toxicity. In T. niphobles, the proportion of toxic specimens exceeded 90% for the ovary and skin, 60-80% for the fins, liver, intestine, and gallbladder, and 4.5% for the muscle; no toxicity was detected in the testis or eyeball using the mouse bioassay. The highest toxin levels were thousands (2,291-7,777) of MU per gram in the liver, intestine, ovary, and gallbladder, hundreds(146-328) of MU per gram in the skin and fins, and 18 MU/g in the muscle. Takifugu niphobles toxicity also exhibited remarkable regional variation. The toxicity in the edible muscle of T. pardalis and T. niphobles was at acceptable levels for human consumption, while the toxicity of the skin of both species of puffer fish was very high, so that care must be taken when used for human consumption.