Refined rapeseed oil was transesterilled at 60degreesC with MeOH and 0.3% of (Li, Na, K, or Cs)OH as catalyst. The stronger the catalyst base, the faster was the reaction and the higher was the yield (K) of Me esters, e.g., 48.2% (LiOH) and 78.8% (CsOH). The progress in transesterification was measured in terms of the resulting glycerol that was determined in 15, 30, 60, 90 and 120 min of the reaction course. A complete factorial (x) design 2 3 was used to study the KOH-catalyzeq transesterification in relation to temperature (x(1) = 20-50degreesC), KOH concentration (x(2) = 0.15-0.9%), and MeOH/OR mole ratio (x(3) 1:1-5:1). For each reaction time, a regression equation K = f(x(1), x(2), x(3)) was determined. The rise in each x, resulted in higher K, the smallest and the highest K-increments being due to the rise in x(1) and x(2), resp. At 50degreesC, 0.9% KOH, and MeOH/OR = 6:1, K was 80.3%.