Tamarind seed xyloglucan (TSX) and kappa-carrageenan (KC) have been widely used in the food and pharmaceutical industries. Their synergistic effects and the gelation and degelation of the blends, and the release a hydrophilic model drug, nicotinamide, from the blends were investigated. The KC/TSX blend with a ratio of 1 % (w/v) of KC to 1 % (w/v) of TSX (1KC/1TSX) exhibited the highest synergistic effect. The sol-gel and gel-sol transition temperatures of the blends shifted to higher temperatures when compared with KC alone. The interactions between KC and TSX in the gel state were revealed by ATR-FTIR showing the significant differences in the position and intensity of the peaks at 1164, 1124 and 1130 cm(-1) for the 1KC/1TSX gel sample. These were probably due to the intermolecular hydrogen bonds between the OH and C-O-C groups of KC and TSX. In addition, the sol and gel states of the KC or KC/TSX blends could be differentiated using ATR-FTIR. Furthermore, the time needed to release 90 % (T-90) of nicotinamide alone and nicotinamide from 2KC, 1.5KC/0.5TSX, 1KC/1TSX and 0.5KC/1.5TSX was 17, 66, 75, 95 and 78 min, respectively. This demonstrated a sustained release of the drug when incorporated into the KC or KC/TSX blends in the freeze-dried samples. Moreover, the blends retarded the release better than KC alone. The blend of 1KC/1TSX, that exhibited the highest synergism, provided the most effective retardation of the compounds.