New polyimides containing diamantane units were prepared by a conventional two-step method starting from 1,6-diaminodiamantane and aromatic dianhydrides. The intermediate poly(amic acid)s had inherent viscosities of 0.33-0.55 dL/g. These polyimides did not decompose below 400 degrees C in air or nitrogen atmosphere, and the temperature at 5% weight loss were above 491 degrees C. The glass transition temperatures of the polyimides were found to be 375-429 degrees C by DSC. These polyimides had almost the same semicrystalline patterns and exhibited crystalline diffraction peak (2 theta) at around 15 degrees. The polyimide Vb exhibited a melting endothermic peak at 514 degrees C.