  We give an effective estimation from above for the local {\L}ojasiewicz
exponent for separation of semialgebraic sets and for a semialgebraic mapping
on a closed semialgebraic set. We also give an effective estimation from below
of the {\L}ojasiewicz exponent in the global separation for semialgebraic sets
and estimation of the {\L}ojasiewicz exponent at infinity of a semialgebraic
mapping similar to the Jelonek result in the complex case.
