We investigate the static and dynamic performance of 4H-SiC GTO thyristors made on epitaxial layers grown on n+ substrates. The forward voltage drop is found to be 4.5 - 5 V measured at 100 A/cm(2) and 200 degreesC and a forward blocking voltage of up to I 100 V is measured. A large forward drop at room temperature (12-15 V) is attributed to incomplete ionization and bandgap narrowing in the p+ anode. The transistor current gains inherent to the GTO thyristor are measured as functions of current and temperature. The fabricated devices show large turn-on gain and small turn-off gain, consistent with the comparable npn and pnp transistor current gains.