DNA polymerases from the yeast and mycelial phases of a fungus, Histoplasma capsulatum, were partially purified and analyzed. Two classes of enzymes were identified in each morphological form. No significant differences were found among polymerases Ia and Ib from mycelia and I from yeast; similarly, polymerases II from both phases were almost identical. (Numbering refers to the order of elution from phosphocellulose.) However, all of the class I polymerases differed significantly from the class II enzymes. DNA polymerases I ( M r 122,000) were unaffected by 0.2 m KCl and resistant to 10 m m N-ethylmaleimide; their levels fluctuated significantly in relation to cell growth, and they showed no nuclease activity. All of the enzymes had similar template dependence and Mg 2+ requirements. These results are compared to data on other eucaryotic DNA polymerases. Possible roles for class I and class II polymerases are discussed.