The W' is a charged, heavy, vector boson predicted to exist by some extensions
of the standard model.  We have searched for the processes W' --> e nu and W'
--> mu nu for M(W') > 100 GeV/(c**2), in p anti-p collisions at s**(1/2) = 1.8
TeV, using data taken with the Collider Detector at Fermilab.  The
nonobservation of these processes leads to a lower limit of 520 GeV(c**2)
(95% confidence level) on the masss of the W', assuming standard-strength
couplings to three fermion generations.