  We report the discovery of a pair of z = 4.25 quasars with a separation of 33
arcseconds. The brighter of the two objects was identified as a high-redshift
quasar candidate from Sloan Digital Sky Survey multicolor imaging data, and the
redshift was measured from a spectrum obtained with the Hobby-Eberly Telescope.
The slit orientation of this observation {\it by chance} included another
quasar, approximately one magnitude fainter and having the same redshift as the
target. This is the third serendipitous discovery of a z > 4 quasar. The
differences in the relative strengths and profiles of the emission lines
suggest that this is a quasar pair and not a gravitational lens. The two
objects are likely to be physically associated; the projected physical
separation is approximately 210 $h_{50}^{-1}$ kpc and the redshifts are
identical to $\approx$ 0.01, implying a radial physical separation of 950
$h_{50}^{-1}$ kpc or less. The existence of this pair is strong circumstantial
evidence that $z \sim 4$ quasars are clustered.
