  We show that the Z-strings of the standard electroweak theory can be
stabilized by strong external magnetic fields, provided that $\beta^{1/2}
\equiv M_H/M_Z\leq 1$, where $M_H$ and $M_Z$ are the Higgs and Z masses. The
magnetic fields needed are larger than $\beta^{1/2} B_c$ and smaller than
$B_c$, where $B_c\equiv M^2_W/e$ is the critical magnetic field which causes
W-condensation in the usual broken phase vacuum. If such magnetic fields were
present after the electroweak transition, they would stabilize strings for a
period comparable to the inverse Hubble rate at that time. Pair creation of
monopoles and antimonopoles linked by segments of string is briefly considered.
