Functional polymer micro- and nanoparticles with novel morphology are of great importance because of their wide range of applications in complex biological systems and nanotechnology. Due to the outstanding advantage of the absence of any surfactant, precipitation polymerization as a heterogeneous polymerization technique has been developed to prepare various uniform and clean polymer particles, such as microspheres, nanoparticles, core–shell particles, core–double shell particles, single-shell hollow particles, double-shell hollow particles, and rattle-type hollow nanostructures. In this review, a general introduction into the categories of precipitation polymerization and their mechanisms is presented. The precise control of particle size, size distribution, pore size, morphology and surface chemistry of micro- and nanoparticles, core–shell hybrids and polymer hollow structures is discussed. The development of complex nanostructures and their applications in separation, drug delivery and nano-reactor systems are highlighted as well.