Surface properties of Ti-containing adsorbents such as Ti-silica gel, Ti-Al beta zeolite,two samples of TS-1 zeolite prepared in different ways, as well as of pure silicalite were studied by means of IR spectroscopy of CO adsorbed at low temperatures. Surface silanol groups, acidic bridged hydroxyls, coordinatively unsaturated Ti and Al atoms were characterized as adsorption sites. The capability of IR spectroscopy of adsorbed CO to distinguish between TS-1 samples of different origin is demonstrated.