The inclusive charged particle transverse momentum distribution is measured in proton-proton collisions at sqrt (s) = 900 GeV at the LHC using the ALICE detector. The measurement is performed in the central pseudorapidity region(|nyu| <0.8) over the transverse momentum range 0.15 <pT <10 GeV/c. The correlation between transverse momentum
and particle multiplicity is also studied. Results are presented for inelastic (INEL) and non-single-diffractive(NSD) events. The average transverse momentum for |nyu| <0.8 is (pT) INEL = 0.483±0.001 (stat.) ±0.007 (syst.) GeV/c
and (pT) NSD = 0.489 ± 0.001 (stat.) ±0.007 (syst.) GeV/c, respectively. The data exhibit a slightly larger (pT) than measurements in wider pseudorapidity intervals. The results are compared to simulations with the Monte Carlo event
generators PYTHIA and PHOJET.