Use of silver (Ag) nanoparticle suspension for various applications such as ink-jet printing of electronic circuits has been of prime interest. We observed the microstructure evolution of the inkjet-printed Ag thin films on Si substrates under various annealing conditions using the field-emission scanning electron microscopy (FE-SEM). Abnormal grain growth characteristics were identified when annealed at about 240 oC under ambient air. Growth characteristics of pores were found to be in accordance with that of grains. Competition between grain and pore growth is attributed to small grain sizes, low packing density and high porosity, which are characteristic of inkjet-printed Ag films as dried.