Considerable damping-off of the seedlings of several commercial Apiaceae plant species was observed in Serbia. The infection of a total of 48 seed samples of nine vegetable and spice plants with phytopathogenic Alternaria spp. was established using the deep-freeze-blotter method. Identification of Alternaria species was performed using both conventional methods and PCR. Four different plant-pathogenic Alternaria species were detected in Serbia: A. dauci, A. radicina, A. petroselini, and A. alternata, all of which caused reduction of carrot, parsley, parsnip, and celery seed emergence. Alternaria dauci, A. radicina, and A. petroselini were relatively more aggressive compared to A. alternata. Substantial seed infection levels and strong influence of Alternaria spp. on seed emergence indicated that production of Apiaceae seed needs to be improved in order to obtain pathogen-free seed.