This study was carried out to make a search for the usefulness of marigold plants (Tagetes erecta) as a natural dye. And we have also examined into the dyeability and antifungal activity of silk and cotton fabrics dyed with 2% powdered colorant and 1% liquid colorant. Almost surface colors of silk and cotton fabrics dyed with 2% powdered colorant and that dyed with 1% liquid colorant except for that treated Cu and Fe with mordants were shown by Y-level. $L^*$ values of silk fabrics dyed with 2% powdered colorant were 66.2 to 86.39, those $a^*$ values were -1.97 to 6.09, and those $b^*$ values were 13.69 to 35.97. And $L^*$ values of cotton fabrics dyed with 2% powdered colorant were 78.97 to 89.62, those a values were -3.39 to 0.38, and those $b^*$ values were 5.63 to 15.61 $L^*$ values of silk fabrics dyed with 1% liquid colorant were 34.37 to 85.57, those a values were -7.79 to 12.33, and those $b^*$ values were 15.13 to 82.91, And $L^*$ values of cotton fabrics dyed with 1% liquid colorant were 44.12 to 87.90, those $a^*$ values were -8.37 to 6.18, and those $b^*$ values were 11.65 to 78.87. Colorfastness of silk fabrics against light treated nothing with mordants and that dyed with 1% liquid colorant decreased for a little by second grade, however, that against washing, rubbing, perspiration and dry cleaning were increased over fourth grade. Colorfastness of cotton fabrics in terms of rubbing, light, and dry cleaning, except for washing and perspiration, were shown by over third grade, when that was treated nothing with mordants. Antifungal activities of silk fabrics treated nothing with mordants and dyed with 1% liquid colorant of marigold extracts were shown by 28.9% against Staphylococcus aureus. However, those of Al, Ca, Cu and tartaric acid mordanting were more than 25.5% against Staphylococcus aureus and Klebsiella pneumoniae.