Electrically conductive silicone rubber composites have been prepared through incorporation of conductive acetylene black and short carbon fibre (SCF). The percolation limit for the attainment of high conductivity is found to be relatively less for silicone rubber based composites compared to EPDM or NBR based composites reported earlier. Percolation limit is found to be lower for SCF-filled systems (7.5 phr) compared to black-filled ones (14 phr). Both black-and SCF-filled systems exhibit an increase in resistivity with the increase in temperature (PCT effect). This PCT effect may be explained in terms of differences in the thermal expansion between the rubber matrix and the conductive filler. However, resistivity-versus-temperature plots are not identical during the heating-cooling cycle, leading to some hysteresis and electrical set. The current-voltage relationship is linear (Ohmic in nature) at room temperature but becomes non-linear (non-Ohmic) at elevated temperatures. The resistivity of these composites is measured under different conditions such as on applying pressure and being subjected to different mechanical stress and strain over the specimens. An effort has been made to correlate the effect of different parameters on electrical resistivity with the change in the conductive network structure under different conditions. ZUSAMMENFASSUNG: Elektrisch leitende Silikonkautschuk-Verbundwerkstoffe wurden durch Fu ¨llen mit leitfa ¨higem Acetylenruß bzw. kurzen Kohlenstoffasern (SCF) hergestellt. Die Perkolationsgrenze fu ¨r das Erreichen einer hohen Leitfa ¨higkeit liegt bei Silikonkautschuk-Verbundwerkstoffen relativ niedrig im Vergleich zu den bereits beschriebenen Verbundwerkstoffen auf EPDM-oder NBR-Basis. Die Perkolationsgrenze ist bei den SCF-gefu ¨llten (7.5 phr) Systemen niedriger als bei den mit Ruß (14 phr) gefu ¨llten. Sowohl die rußgefu ¨llten als auch die SCF-gefu ¨llten Systeme zeigen eine Erho ¨hung des spezifischen Widerstands mit der Temperatur (PCT-Effekt). Dieser PCT-Effekt kann mit dem unterschiedlichen thermischen