Poly(styrene) microgels are known, but the influence of tacticity on particle formation and behavior has not been investigated yet. Isotactic poly(styrene) (iPS) with M-n=15-120kg/mol is synthesized by coordinate polymerization and cross-linked by Friedel-Crafts alkylation in a miniemulsion. Nuclear magnetic resonance (NMR) spectroscopy, light microscopy, cryogenic transmission electron microscopy, and wide-angle powder diffraction are applied to understand the structure of microgels obtained. Typically, spherical microgels with overall diameter of 40-500 nm are found. Isotacticity of the polymer is retained during microgel formation. Increase of cross-linker content leads to partial crystallinity inside the microgel. (c) 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 175-180