Nosemosis is the most common disease in honey bee Apis mellifera L., and is a major issue related to bee health worldwide. Therefore, the purpose of this research study was to determine prevalence of microsporidia parasitic infection of the genus Nosema spp. in East Kazakhstan Region (EKR). In the years of 2018 –2021, 394 honey bee samples were collected at 30 apiaries located in four districts of East Kazakhstan Region (Katon-Karagay, Urzhar, Borodulikhinsky, and Shemonaikhinsky). In order to determine the level of infestation, firstly, the presence of Nosema spp. spores was detected using optical microscopy, and then the average amount of spores per bee was counted using a hemocytometer. The degree of nosemosis prevalence was determined in points by means of a semi-quantitative method, and as a percentage from the total of samples and of the amount of positive tests. At the outcome of the study, microsporidia of the genus Nosema spp. were detected in 23.3% of cases (92 samples). Prevalence at its low degree was found in six samples (1.5%), at an average degree in 55 samples (14%), and at a high one in 31 samples (7.9%). This research study proved that microsporidia of the genus Nosema spp. are widely spread at the apiaries of East Kazakhstan Region in different orographic and climatic conditions. Notwithstanding that it was impossible to statistically determine any significant differences between the dependence of nosemosis prevalence and the apiary location, this indicator is actually higher in the mountainous regions than in the steppe. Concurrently, a close inverse correlation was recognized between the amount of spores in one bee and the level of infestation in bee families from the duration of the vegetation season at the apiary location. This gives grounds to assert that the environmental factors have an impact on formation and development of nosemosis. The results of the research presented in the article indicate the need for further research aimed at increasing the number of studied apiaries, and above all the use of molecular biology methods to distinguish the species that cause nosemosis infection (PCR).