In this paper, the most recent results on jet fragmentation
obtained at the Collider Detector at Fermilab Tevatron are presented.  The
multiplicity and momentum distribution of charged particles inside jets in
dijet events are compared to the predictions of the Modified Leading Log
Approximation complemented with the hypothesis of Local Parton-Hadron
Duality.  The two parameters of the model are extracted, the cut-off scale
Q_eff = 230 +/- 40 MeV and the rate of parton-to-hadron conversions
Kcharged_LPHD = 0.56 +/- 0.10.  A fit of the data for the ratio of
multiplicities in gluon and quark jets r, where r is treated as a free
parameter, resulted in r = 1.8 +/- 0.4.  Also, we compared the charged
particle multiplicities in dijet and gamma-jet events.  The comparison
allowed for an extraction of a model-independent ratio of multiplicities in
gluon and quark jets.  We report r = N_g/N_q = 1.61 +/- 0.11(stat) +/-
0.28(syst) for E_jet = 40 GeV.