The performance of the CDF end-plug calorimeter is described.  We
determined the energy resolutions to be sigma/E = 14.5%/sqrt E oplus 0.7% for
electrons and sigma/E = 68.0%/sqrt E oplus 4.1% for charged pion, where E is
the energy measured in GeV.  The response linearities satisfied our
requirements.  The response variations on the surface of a typical tower were
measured to be 2.3% for e+ and 1.6% for pi+.  For the photon conversion
detection by the preshower detector, we obtained the detection efficiency for
two minimum ionizing particles to be 90-100% for the phototube gains of (1-4)
x 105.  The rate of pi+'s depositing large fractions of energy in the
electromagnetic section could be reduced by factors of 1.4-2.0 with keeping
95% efficiency for e+.