In this article, we present an experimental study of the formation of a Langmuir-Blodgett (LB) monolayer of alkanethiol-encapsulated gold particles. We developed a procedure for preparing the LB spreading suspension from an aqueous gold colloid, and we fabricated a large-scale densely packed monolayer of alkanethiol-encapsulated particles covering an entire substrate using the LB technique. Scanning electron microscopy observations demonstrated that this LB monolayer is composed of domains of ordered close-packed encapsulated gold particles, some of which extended to about 10 mum in extent. A detailed study of the forming mechanism of the LB monolayer of gold particles indicates that the ordered particle domains were formed by a self-organization process induced by the evaporation of the spreading suspension before LB compression. These domains were then aggregated to a densely packed monolayer by the compression process. The proposed method provides a feasible procedure for fabricating a variety of new nanostructured materials.