This report presents activities and results obtained in the project Materials for Optical Signature Suppression, during the period 2001-2003. The main goal has been to select or develop materials, surface coatings or material structures capable of giving a low signature in the thermal wavelength region, in order to decrease the signature of e.g., vehicles and other platforms of the Swedish Armed Forces. Different types of infrared (IR) reflective pigments have been developed, for use in low emissive camouflage paint. In collaboration with PvTT in Finland we have been involved with the development of such paint. In particular, we have been interested in surfaces and pigments with wavelength dependent characteristics, such as a visually low reflecting surface combined with high IR reflectance, or a high reflectance only in the atmospheric transmission windows (3-5 and 8-12 µm). In the case of the latter, cooling by radiation will be allowed outside of these transmission windows. We have shown that the visual reflectance can be reduced, e.g., by using oxidized metal pigments or multi-layered pigments. Using photonic crystals we can obtain high reflectance in the 3-5 and 8-12 µm windows, only. These characteristics have been obtained by modelling and material synthesis has started. In order to enhance the contrast between target and background, we anticipate the future use of polarization sensitive IR sensors. In order to meet this threat, we have developed surfaces that depolarize radiation and, thus, give a similar polarized signature as a typical ground background. In order to meet future demands on camouflage we have initialed a litterature study in the area of adaptive camouflage.