The transversity distribution function can be studied in inclusive one- and two-hadrons production in DIS off a transversely polarized target.
The measurement of the spin asymmetries in the azimuthal distribution of the one- or two-hadrons, and of the Collins or di-hadron fragmentation functions, allows to access the transversity distribution function. In this thesis the measurements of the one- and two-hadron transverse spin asymmetries performed
by the COMPASS experiment is discussed. Finally the first extraction of the transversity PDF from two-hadron asymmetries is perfomed.
