The gut microbiome is related to various host health conditions through metabolites produced by microbiota. Investigating their relationships involves association analysis of the population-level microbiome and metabolome data, which requires the appropriate collection, handling, and storage of specimens. Simplification of the specimen handling processes will facilitate such investigations. As a pilot study for population-level studies, we collected the fecal samples from three volunteers and tested whether a single sample collection procedure, particularly using OMNIgene-GUT, can be used to reliably obtain both microbiome and metabolome data. We collected fecal samples from three young and healthy Korean adults, stored them at room temperature with and without OMNIgene-GUT solution up to three weeks, and analyzed their microbiome and metabolite profiles. We found that the microbiome profiles were stably maintained in OMNIgene-GUT solution for 21 days, and the abundance relationships among metabolites were well preserved, although their absolute abundances slightly varied over time. Our results show that a single sampling procedure suffices to obtain a fecal sample for collecting gut microbiome and gut metabolome data of an individual. We expect that the health effects of gut microbiome via fecal metabolites can be further understood by increasing the sampling size to the population level.