The fungi and fungus-like (straminipilous) organisms growing on the eggs of Acipenser sturio, A. persicus colchicus, A. oxyrhynchus and Polyodon spathula in water of different trophy have been investigated. A total of 61 species including 56 fungus-like organisms and 5 fungal species were recorded. The largest number of species occurred on eggs in water from river Biała (more biogenic), the smallest in water from river Supraśl (poor     in biogenes). Achlya polyandra, Aphanomyces irregularis, Saprolegnia ferax, S. parasitica, Leptomitus lacteus and Pythium diclinum were found on the eggs of all investigated species of sturgeon. Aphanomyces pisci, Dictyuchus pisci, Saprolegnia bhargavae and Scoliolegnia subeccentrica were noticed for the first time in Polish waters.