The effects ofFusarium oxysporumf. sp.apiion celery seed germination were investigated with the hope of developing a germ-plasm screening procedure with seeds. Seeds of celery lines known to exhibit a range of disease responses to the pathogen as whole plants were inoculated with two different virulence types and in two ways: (1) spore–mycelial suspensions in potato dextrose broth (PDB), and (2) spore–mycelial suspensions in sterile H2O. Inoculum in PDB retarded germination in all celery lines and the relative degree of this retardation was congruent with virulence of the pathogen and, in general, relative retardation of germination was also in agreement with whole-plant disease response. Inoculum in H2O stimulated germination and the degree of stimulation also appeared related to degree of whole-plant disease response. Extracts from disease lesions incited byF. oxysporumf. sp.apiion celery exerted a dose-dependent inhibition of germination but filtrates from 14-day-old cultures in PDB had no significant effect.