We studied the effect of all-trans-retinoic acid (RA) on the expression of several surface lectin receptors and cell membrane fluidity of mouse forestomach carcinoma cell line (MFC) in vitro. The results showed that cells treated with IRA manifested decreased expression of lectin receptors, increased membrane fluidity and reduced spontaneous metastasis. These results suggest that the effect of RA on minor cell membrane may be one of the mechanisms involved in the alternation of cell metastatic phenotype.