An experiment was carried out to establish a new method for the isolation of protein and nucleic acid from single cell employing an Impact-Cell-Mill. Chemical pretreatment with 0.7 N perchloric acid gave a good result to isolate nucleic acid from Baker's yeast. About 85 % of protein was obtained using an Impact-Cell-Mill after the treatment of 0.7 N perchloric acid. Concurrent treatment of an Impact-Cell-Mill and chemical procedure gave also a good result. In this case, 0.7 N perchloric acid and 40 γ/ml of ribonuclease were used, and about 70% of nucleic acid was isolated and 85 % of protein was recovered with the treatment of an Impact-Cell-Mill. The third is an utilization of an Impact-Cell-Mill as a reactor. In this case, adding 180 γ/ml of ribounclease, nucleic acid was isolated about 90 % and 95 % of protein was obtained from the supernatant of yeast suspension treated with an Impact-Cell-Mtll.