It was found that treatment in intense electric fields (i.e., electrical poling) changed the microstructure and filtration performance of polyvinylidene fluoride (PVDF) microfiltration membranes. The effect of temperature, sample size and time on the electrical breakdown of membranes was studied. It was shown that the hydraulic permeability and flux of the membranes can be tuned by changing the poling time. The effect of electrical poling on rejection and molecular weight cutoff was more significant. It was also found that the electrical breakdown of PVDF membranes is a gradual process and a long exposure time to an intense electric field can have adverse effects on the separation performance of the membranes.