Pinus caribaea seeds were IDS-treated i.e. incubated and dried to four levels of moisture content followed by separation in water. The separation was optimal after drying for 21/2-51/2h, i.e. to 21-25% moisture content. The germination capacity was thereby increased from 23% to 54%, and the 1000-seed weight was increased from 12 g to 13.5 g. After treatment it was possible to dry the seed to 7% moisture content without loss of germination capacity. The IDS-method is recommended for upgrading seed of P. caribaea.