[en] Highlights: • Dietary morin prevents muscle wasting caused by cancer cachexia. • Morin suppresses growth of lewis lung carcinoma (LLC) cells, but not C2C12 myotubes. • Morin binds to ribosomal protein S10 in LLC cells. Cachexia, observed in most cancer patients, is a syndrome that includes wasting of bodily energy reserves and is characterized by muscle atrophy and fat loss. We have previously demonstrated that isoflavones, such as genistein and daidzein, prevent muscle wasting in tumor-bearing mice. In this study, we examined the effect of morin, a flavonoid, on cachexia. The wet weight and myofiber size of muscles in Lewis lung carcinoma (LLC) cell-bearing mice fed a normal diet were decreased, compared with those in control mice fed a normal diet. In contrast, intake of morin prevented the reduction of muscle wet weight and myofiber size. Moreover, the tumor weight in mice fed the morin diet was lower than that in mice fed the normal diet. Both cell viability and protein synthetic ability of LLC cells were reduced by treatment with morin, but C2C12 myotubes were not affected. Binding assay using morin-conjugated magnetic beads identified ribosomal protein S10 (RPS10) as a target protein of morin. Consistent with the result of morin treatment, knockdown of RPS10 suppressed LLC cell viability. These results suggest that morin indirectly prevents muscle wasting induced by cancer cachexia by suppressing cancer growth via binding to RPS10.