We study the structural formation of dendrimers by stochastic molecular dynamics simulations. The density profile under different pH condition is clarified numerically. We find that the structural change of dendrimers strongly depends on the solvent quality. We also investigate the effective interaction between nanosized dendrimer molecules. It is demonstrated that the effective interaction between like‐charged dendrimers becomes attractive when the electrostatic coupling is strong. © 2004 American Institute of Physics