The quality of planted seeds has a critical influence on the ability of crops to become established and to realize their full potential of yield. Loblolly pine (Pinus taeda L.) and slash pine (Pinus elliottii Engelm.) are forest trees species, both native to the southern United States of America, mostly planted in Northeastern Argentina for site restoration and forest management due to their fast growth on diverse sites. Numerous diseases attack these two pine species in forest nurseries: damping-off and root rot. Many Fusarium species present on seeds were found to be associated with damping-off and root diseases in loblolly and slash pine seedlings. Seed of Pinus elliottii and P. taeda were collected from Northeastern Argentina and analyzed for seed-borne Fusarium. Seed treatments as running water for 24 and 48 h were tested for effectiveness in changing Fusarium populations on seeds. Seven different species of Fusarium were isolated from the seed lots assayed: F. solani, F. verticillioides (= F. moniliforme), F. oxysporum, F. proliferatum, F. incarnatum (= F. pallidoroseum = F. semitectum), F. equiseti and F. acuminatum. Fusarium populations detected on seeds changed after running water treatments for 24 and 48 h but this changes varied among seedlots. This is the first report on Fusarium species associated with P. elliottii and P. taeda seeds in Argentina.