We examined the activities of nine enzymes in microsporidian spores, which were purified out of the fat body of the crickets Gryllus bimaculatus. A special method of spore purification, which included a centrifugation in glycerine density, incubation in lysozyme and Triton X-100 before homogenization, and washing, has been specially elaborated for the present study. The activities of following enzymes were studied: glucose-6-phosphate dehydrogenase (EC 1.1.1.49), phosphoglucose isomerase (EC 5.3.1.9) and pyruvate kinase (EC 2.7.1.40). Specific activities for each enzyme were respectively: 14.1 ± 0.9, 1325.8 ± 209.3, 5.9 ± 0.5 nmol/min · mg protein. We did not discovered a reliable activities in hexokinase (EC 2.7.1.1), phosphoglucomutase (EC 5.4.2.2), lactatedehydrogenase (EC 1.1.1.27), NAD-dependent malatdehydrogenase (EC 1.1.1.37), alcohol dehydrogenase (EC 1.1.1.1) and succinatedehydrogenase (EC 1.3.99.1) by means of methods used. The data achieved indicate that glycolysis probably plays an important role in the energetic metabolism of microsporidia. The extremely high activities of the phosphoglucose isomerase, as well as the lack of activities of hexokinase and phosphoglucomutase, at least in the limits of the sensibility method, suggest the possible utilization of glucose-6-phosphate from host cells as the main source of an energy. It is remarkable that the conversion of glycogen of free glucose into trehalose is an important functon of the insect fat body, tha main site of microsporidia development. Trehalose is formed of glucose-6-phosphate and UDF-glucose. It is likely that glucose-6-phosphate is produced very intensively in the cells of the fat body. The partial involvement of glucose-6-phosphate in the pentose-phosphate pathway is also possible. The absence of lactatedehydrogenase activities leaves open the question of the final products of the carbohydrate katabolism in microsporidia and of mechanism of reoxidation of the reduced NADH forms produced during the glycolisis.