This study was undertaken to examine the effect of sea tangle and sea mustard on physiochemical and sensory characteristics of cakes and the possibility commercialization of these functional cakes. The moisture contents of cakes prepared with sea tangle and sea mustard were higher than those of control, and a positive correlation between water holding capacity(WHC) and moisture contents was observed(r=0.836). As addition level of sea tangle and sea mustard was increased, volume of cakes were decreased, whereas hardness was increased slightly and color became deep. Hardness was strongly correlated to the volume of cakes(r= 0.914). Visual observation by photomicrography showed that, as addition level of sea mustard and sea tangle was increased, formation of air cells were prohibited and thus volume of cakes was decreased. The microstructural observation by scanning electron microscopy(SEM) showed that air cells of cakes were well developed up to 5% addition of sea tangle powder. As a result of the sensory evaluation for the cakes prepared with sea tangle and sea mustard, no significant difference was observed between control and those addition levels up to 5%. Flavor was proved to be the most important factor in determining overall acceptability and hedonic hardness score was inversely correlated to the objective hardness value(r= 0.853).