  We calculate the soft SUSY breaking terms arising from a large class of
string scenarios, namely symmetric orbifold constructions, and study its
phenomenological viability. They exhibit a certain lack of universality, unlike
the usual assumptions of the minimal supersymmetric standard model. Assuming
gaugino condensation in the hidden sector as the source of SUSY breaking, it
turns out that squark and slepton masses tend to be much larger than gaugino
masses. Furthermore, we show that these soft breaking terms can be perfectly
consistent with both experimental and naturalness constraints (the latter comes
from the absence of fine tuning in the $SU(2)\times U(1)_Y\rightarrow
U(1)_{em}$ breaking process). This is certainly non--trivial and in fact
imposes interesting constraints on measurable quantities. More precisely, we
find that the gluino mass ($M_3$) and the chargino mass ($M_{\chi^{\pm}}$)
cannot be much higher than their present experimental lower bounds
($M_3\stackrel{<}{{}_\sim}285\ $GeV ; $M_{\chi^\pm}\stackrel{<}{{}_\sim}80\
$GeV), while squark and slepton masses must be much larger
($\stackrel{>}{{}_\sim} 1\ $TeV). This can be considered as an observational
signature of this kind of stringy scenarios. Besides, the top mass is
constrained to be within a range ($80\
$GeV$\stackrel{<}{{}_\sim}m_t\stackrel{<}{{}_\sim}165\ $GeV)
