Screening fields, at or below which 10%, 30% and 50% of TiO2 ceramic samples would break electrically, were applied to samples which show single-mode strength distribution. After these high-voltage screenings, the surviving samples were subjected to mechanical strength measurement and the resultant strength distributions were compared with the original distributions. This high-voltage screening was also applied to model ceramics samples composed of titania with two different relative densities. The effect of high-voltage screening and the correlation between mechanical and dielectric strengths are discussed.