Mechanism of charge transport through GaSb p-n homojunctions prepared by low pressure metal organic vapour phase epitaxy technology was studied. Calculation of current-voltage characteristics based on Shockley-Read-Hall recombination model was performed accounting for specific features of the band structure of GaSb with the lowest minimum of the conduction band at T point and higher minima at L points. It is shown that this type of transport prevails if the samples were prepared at higher growth rate. Analysis of temperature dependencies of some parameters of the experimental characteristics gave, besides the expected value of band gap energy, also the activation energy of the recombination level as (E-c-0.22) eV or (E-v+0.29) eV. The latter value agrees reasonably well with published data on deep levels in GaSb. On the other hand, the charge transport in more slowly grown samples was nearly temperature independent, especially in the reverse direction, probably due to prevailing tunnelling mechanism. (C) 2003 Elsevier Science Ltd. All rights reserved.