The aim in this study was to produce multifunctional cementitious composites with advanced thermal and electrical performance, considering that these composites have high conductivity and can be used in, for example, deicing, electromagnetic shielding, antistatic or anticorrosion applications. Carbon fibre (CF) and carbon powder (CP) were used singly or together to develop cementitious composites with high conductivity. Electrical resistance and thermal conductivity tests were performed to measure the conductivity of the cementitious composites, while a minispreading test was applied to assess the consistency of the fresh-state cementitious composites containing conductive materials, to determine the distribution of the incorporated conductive material, and scanning electron micrographs were analysed. In addition, compressive strength tests were conducted to determine the composites’ mechanical properties. According to the test results, the lowest electrical resistance (197 Ω on the first day) was obtained from binary mixtures, while the highest thermal conductivity (1250 mW/m.K on the seventh day) was obtained from mixtures containing only CP (0.6 vol%). The mixture with 0.5% CF by volume performed worst in terms of mechanical and workability, with 20.5 MPa less compressive strength and 16 cm less minispread diameter values, compared with the control mixture.