The main theme of this research was to synthesize nanoparticles using green materials in a spinning disk reactor (SDR), which is a type of Higee equipment. The reducing agent and protecting agent were glucose and starch, respectively, either of which is an inexpensive and nontoxic material. Silver particles were prepared by continuously pumping two solutions, which were a mixture of AgNO3 aqueous solution containing protecting agent and another mixture of NaOH aqueous solution containing the reducing agent, into the chamber of the SDR, where a liquid-liquid reaction took place. The reaction time was less than 10 min, which was much shorter than the traditional methods. After washing and redispersing, silver particles of 10 nm or smaller were obtained, and the redispersed aqueous suspensions were stable for more than 40 days with or without the addition of a dispersing agent. A high-gravity process that combines economic benefit with environmental benignancy was successfully developed to produce silver nanoparticles. (c) 2007 American Institute of Chemical Engineers.