Lentinus strigosus is an edible and medicinal species of mushroom found in Central Luzon, Philippines. In the current study, the effects of ethanolic extract of L. strigosus mycelia (grown on coconut water in submerged culture) on the food intake and locomotion of Caenorhabditis elegans were investigated. Chemical compositions of the mushroom mycelia were likewise analyzed. Results showed that mycelial extract significantly reduced the food intake and increased the roaming and dwelling activities of extract-treated nematodes. The presently observed positive effects could not be accounted to the toxicity of the mycelial extract since the extract was confirmed safe in the acute lethality assay. In addition, mycelia of L. strigosus contained valuable mycochemicals such as flavonoids, alkaloids, terpenoids, steroids, phenols, saponins, athrones, anthraquinones, and coumarins, which have been reported to play important roles in the different mechanisms of anti-obesity activity. Accordingly, L. strigosus mycelium is a new addition of functional food resources, which has promising potential for the prevention of obesity and associated diseases.