Abstract: Measurement of thermal expansion coefficients of solid materials with the thermal dilatometric attachment of Shimadzu DT-2A differential thermal analyser was described. The dilatometer was calibrated with pure copper (99.95%) in the temperature range of RT-900℃ in order to get the instrumental constant. By checking with Fe and Ni samples of known thermal expansion coefficients, the results obtained are found to be in agreement with those from the literature and the differences are less than ±2.5%. Volume expansion ratio of two composites, graphite and glass fibre reinforced plastics, can be calculated through the linear expansion measurements. Approximate equations for calculating volume expansion ratio by curve fitting method were also obtained.