In this study, the effects of fly ash on the electrical resistivity of hardening (setting) cement paste were investigated. Different combinations of water/binder ratio and binder dosage levels were prepared for the mixtures. The fly ash was used in the mixtures by replacing the cement in ratio of 0 %, 10 %, 20 % and 30 % by weight. The measurements were done at room temperature. The relation between electrical resistivity and hydration time with and without electric current application was investigated. The results obtained indicate the influence of fly ash content and water to binder ratio on the electrical resistivity of all the pastes under investigation. As a result, electric current application can be used on the cement paste with high volume fly ash in order to accelerate curing period.