Metabolism of macroergic phosphorus compounds was studied in high- and low-productive isogenic strains of Penicillium chrysogenum. It was shown that the levels of the high-polymer polyphosphates (fractions PP1, PP2 and PP3) in the strain intensively producing penicillin were 2-3 times higher than those in the low-productive strain by the 2nd day of the fermentation process (the period of penicillin production). The levels of pyrophosphate and ATP in the mycelium during the fermentation process did not significantly differ in the strains. The study on the relation between metabolism of the high-molecular polyphosphates and conditions of the culture growth and antibiotic production revealed that their accumulation was connected with biosynthetic processes giving rise to the growth of P. chrysogenum, while their consumption with penicillin production. The dynamics of the pyrophosphatase and polyphosphatase activity in the mycelium of the strains was studied.