Insulation materials are the indispensable elements for the conservation and economy of energy in buildings. This study investigates the thermal conductivity, compressing strength, fire behavior of cellulosic panels and cement based composites made from barley straw. The measured thermal conductivities were 0.071 W/mK for cellulosic panels and 0.11 W/mK for cement based composites on the average. According to the ignitability test, EN ISO 11925-2 classification of cellulosic panels and straw-cement based composites were found as B-class. Most of the composites’ strength values of which changed within the range of 65 to 1270 kPa, conformed to ASTM and Turkish standards