Results of the simulation of star polymers synthesis by one pot, core first method are presented. The simulated ideal living polymerization process consists of two steps. In the first one (core growth) an atom transfer radical polymerization (ATRP) of a crosslinker is performed. When the crosslinker conversion is close, to completion, a bifunctional monomer is added and the ATRP polymerization of the monomer takes place from the obtained cores to form linear arms of the stars. The simulation method is based on dynamic lattice liquid (DLL) algorithm, which takes into account changes of local dynamics resulting from polymerization and formation of complex polymer molecules. In the first stage of the synthesis (core formation), in addition to the effect of concentrations of initiator and crosslinker, the rate of intramolecular crosslinking is also very important. This process "consumes" the reactive crosslinker in the cores, limiting the core size and preventing further star star coupling. The effect of various parameters on star size and internal structure was studied. These parameters involve the rate of intramolecular crosslinking, initial concentrations of the components and the moment of monomer addition. The results can be used as guidelines for the experimental work on star synthesis. (c) 2014 Elsevier Ltd. All rights reserved.