The electrical conductivity of microemulsions comprising C.citratus oil and Tween 20/ethanol (2:1) mixtures in different ratio (10:90, 20:80, 30:70, 40:60) was measured using 100 mM Nacl solution as aqueous phase. The conductivity was measured by Cyberscan CON 11: hand-held conductivity meter (Eutech lnstruments, Singo-pore) using conductivity/TDS electrode cell. The experiment was performed at 25+- 1.0 °C by dipping the electrode into the test sample until equilibrium was reached and reading became stable. The measurements were done in triplicate