In this paper we present the results of a search for nuclearites in the pen
etrating cosmic radiation using the scintillator and track-etch subdetector
s of the MACRO apparatus. The analyses cover the beta = v/c range at the de
tector depth (3700 hg/cm(2)) 10(-5) < beta < 1; for beta = 2 x 10(-3) the f
lux limit is 2.7 x 10(-16) cm(-2)s(-1)sr(-1) for an isotropic flux of nucle
arites, and twice this value for a flux of downgoing nuclearites.