Three DNA polymerases were partially purified from the embryos, liver and mitochondria of the loach Misgurnus fossilis by DEAE- and phosphocellulose chromatography and were identified as DNA polymerases alpha, beta and gamma. DNA polymerase alpha prefers the activated DNA as a template-primer and has a sedimentation value of 6.8S. The enzyme is stimulated by 50 mM potassium phosphate, KCl and, to a lesser extent, NaCl; has a pH optimum of 7.5 and is sensitive to N-ethylmaleimide. DNA polymerase beta also prefers the activated DNA as a template-primer but shows a sedimentation coefficient of 3.0 S. The enzyme is inhibited by salts and has a pH optimum of 8-9; its activity is rather resistant to N-ethylmaleimide. DNA polymerase gamma has a sedimentation value of 6.3S, shows a high activity on poly(A) . oligo(dT) in the presence of 100 mM potassium phosphate and a lesser activity in the presence of 150 mM KCl and NaCl. The enzyme has a pH optimum of 7.0.