In this present study, the preparation of glyoxal--cyclodextrin was investigated in terms of three different molar ratios of -cyclodextrin to glyoxal (1:7, 1: 14 and 1:21), and three reaction temperatures (room temperature (RT), 50C, and 80C) using Al2(SO4)3 as a catalyst. The evidence from FTIR technique was used to confirm the formation of glyoxal--cyclodextrin complexes. The resultant glyoxal--cyclodextrin complexes were applied on cotton using pad-dry-cure process. Based on the amounts of -CD on treated cotton fabrics which were determined by the use of phenolphthalein indicator, the 1:21 molar ratio of -cyclodextrin to glyoxal and room reaction temperature yielded the highest amount of -CD. In order to maintain the whiteness and obtain the high amount of -CD on treated fabric, cotton was dried at 100C for 5 minutes and cured at 130C for 3 minutes. The glyoxal--cyclodextrin treated cotton was washed once to study the durability of the complexes on the fabric. The cotton fabric retained the complexes after a cycle of washing. Vanillin was loaded to the cotton fabric by immersing and padding processes. UV-VIS spectrophotometry was used to analyze the concentration of vanillin on cotton. The results showed that immersing method could load more vanillin on cotton fabric than padding method. During the 25-day experiment, the amount of vanillin on the glyoxal--cyclodextrin treated cotton was higher than the untreated cotton. The results indicated that finishing cotton with glyoxal--cyclodextrin complexes could encapsulate vanillin to be released over a longer period of time.