Nanocrystalline titania have been prepared by thermal decomposition of titanium (IV) n-butoxide in two different solvents (toluene and 1,4-butanediol) at 320 degrees C and employed as supports for Pd and Pd-Ag catalysts for selective acetylene hydrogenation for the first time. The titania products obtained from both solvents were pure anatase phase with relatively the same crystallite sizes and BET surface areas. However, due to different crystallization pathways, the number of Ti3+ defective sites as shown by ESR results of the titania prepared in toluene was much higher than the ones prepared in 1,4-butanediol. It was found that the use of anatase titania with higher defective sites as a support for Pd catalysts resulted in lower activity and selectivity in selective acetylene hydrogenation. However, this effect was suppressed by Ag promotion.