The article provides information on the stability of the niosomal form of cefotaxime. Aliquots of the preparations were stored separately at (4 ± 2) ºС and (22 ± 2) ºС for 180 days. In the stored samples, studies were carried out to determine changes in the main indicators of the quality of niosomal dispersion every ffeen days. The method of dynamic light scattering was used to determine the average size of niosomal particles; to measure the concentration of cefotaxime, the method of highperformance liquid chromatography was used. Data processing and statistical analysis were performed using the R language (version 4.0.2) and the «tidyverse» package. Analysis of group diferences was performed using one-way analysis of variance ANOVA. Diferences were considered signifcant at p <0.05. The niosomal form of cefotaxime, while maintaining the main quality indicators, is stable for up to 90 days at (4 ± 2) ºС. When storing the niosomal form of cefotaxime for 180 days at a temperature of (4 ± 2) ºС, the drug retains the original particle size with a slight decrease in the amount of encapsulated antibiotic (up to 18 %). The low stability of niosomes containing cefotaxime in solution during long-term storage (more than 90 days) is explained, frst of all, by the relatively low molecular weight and hydrolytic stability, as well as by the hydrophilic properties of the active substance. In this regard, it is necessary to further study lyophilized niosomal forms of the antibiotic as more stable and convenient to use.