The development of a new class of antibiotics is urgently needed, because antibiotic resistance became a serious problem in the pharmaceutical and medical fields. Recently, silver compounds, composed of silver and organic molecules, have been developed as effective antimicrobial agents. For instance, silver citrate (Ag3C6H5O7; Ag-Cit) compounds prepared in the form of precipitates can exhibit a strong antimicrobial activity. Ag-Cit compounds were easily prepared in the mixture of AgNO3 and trisodium citrate dihydrate (C6H5Na3O7
2H2O) solutions. Herein, we demonstrated that simple mechanical stirring significantly changed the morphology (shape and size) of Ag-Cit from bulk (bulk Ag-Cit) to rod-like nanostructures (Ag-Cit nanorods). Ag-Cit nanorods exhibited antimicrobial activity stronger than that of bulk Ag-Cit against both Gram-negative and -positive bacteria. These data indicate that the bactericidal activity of Ag-Cit compounds is dependent on their morphology and will provide valuable information for the development of antimicrobial materials based on Ag-Cit compounds.