ABSTRACTA critical comparison of the main parameters playing a role in measurement of electrophoretic mobility of plastic nanoparticles (NPs) by CE and laser Doppler velocimetry (LDV) techniques in NP suspensions is herein presented, accompanied by a discussion about potential impact on different mobility values observed. Capillary material and dynamic or permanent coating of the inner capillary wall, capillary dimensions, EOF variability, BGE temperature, Joule heating, and presence of species potentially interacting with analyzed NPs are underlined as possible causes of the different performance of the above two techniques. It is of importance to get an insight into the reasons behind experimental conditions and operating features to opt for one technique or the other based on research interests. In the end, it is intended to present a knowledge expansion about two parallel paths that converge in a distinctive parameter of an enormous relevance in CE, effective electrophoretic mobility, not achievable by other techniques, and discuss practical considerations in experimental design.