The folacin content of alfalfa (Medicago sativu) and mung bean (Vigna radiutu) sprouts was determined by Lactobacillus casei. Several variations of extraction procedures were tested. The optimum conditions for extraction were autoclaving mung bean and alfalfa sprouts in phosphate buffer containing 0.3% and 0.4% ascorbate, respectively, before homogenisation in a blender. The optimum blending time for folacin extraction was 120 s for mung bean and 15 s for alfalfa sprouts. Folacin content on dry weight basis increased several times in both types of sprouts during germination. Mature alfalfa and mung bean sprouts were found to contain 186 and 178pg folacin per 1OOg fresh weight, respectively.