In the present paper the authors establish conditions for the uniform stabi
lity and the uniform asymptotic stability of equilibria of systems with imp
ulse effects described by systems of nonlinear, time-varying ordinary diffe
rential equations. Under mild additional assumptions, these sufficient cond
itions turn out to be necessary as well. For the case of time-invariant sys
tems,vith impulse effects described by nonlinear ordinary differential equa
tions, the above results are used to establish conditions under which the u
niform asymptotic stability of equilibria can be deduced from the lineariza
tions of such systems.