This study was carried out to investigate the quality characteristics of sponge cake with mesangi(Capsosiphon fulvescens) powder added to give a control 0(control), 2, 4, 6 and 8% by weight per wheat flour. The crude protein was 33.37% for mesangi on a dry basis. Batter specific gravity, viscosity and baking loss increased with increasing mesangi powder content, whereas the specific loaf volume tended to decrease. Values of L and B decreased with increasing mesangi powder content while a value was minimized for the 4% mesangi powder. Hardness, cohesiveness, springiness, gumminess, and brittleness of sponge cakes with added mesangi powder content. The sensory tests indicated that aircell uniformity, firmness, sweetness and overall preference were not affected by the addition of 2 and 4% mesangi powder compared to control. Therefore, the addition of 4% mesangi powder to sponge cake was suggested as bing suitable to improve the quality.