While transverse spin effects have been studied in hadronic interactions si
nce a few decades, investigations with leptonic probes have started very re
cently. Azimuthal distributions of hadrons (mainly pi(+) and pi(-)) produce
d in DIS off transversely polarized targets (proton and deuteron) are studi
ed far the first time in SMC. According to Collins ('Collins effect'), the
adimuthal distribution of the leading hadron might exhibit an asymmetry whi
ch originates from the transverse polarization of the final quark.