A CE method for the characterization of the complex dendrimeric contrast agent Gadomer has been developed and validated. The method was capable of separating the target substance Gadomer 24 from related dendrimers containing amino or carboxyl functions and from impurities of lower molecular weight. The compounds were separated in a fused-silica capillary. The optimized BGE consisted of 15 mM sodium phosphate, pH 6.3, containing 0.5 mM hexadecyltrimethylammonium bromide. The assay was validated with regard to linearity, specificity, accuracy, LOD and LOQ as well As robustness according to the guidelines of the International Conference on Harmonization. The method allows the determination of the purity and stability of the drug substance Gadomer as well as its injectable formulation. On the basis of the present study, a strategy for the quality assurance and quality control of the complex dendrimeric drug candidate Gadomer may be devised. The method may therefore serve as a key component in a set of analytical methodologies designed to assure and control the reproducible quality and safety of this innovative product. To the best of our knowledge, this is the first work reporting a validated method for the characterization, impurity profiling, and stability testing of a dendrimeric agent designed for clinical use.