The uses of the non-ionic detergent Triton X-100 (TX-100) and cationic cetyltrimethylammonium bromide (CTAB) for production of tick-borne encephalitis (TBE) virus subunits were compared. TX-100 split the virus into hemagglutinating envelope components which contain the virion proteins V3 and V1 and into a lipid-free nucleoprotein composed of RNA and V2. The lipid content of released envelope fragments decreased with increasing detergent concentration. By the use of CTAB, the viral glycoprotein V3 could be prepared in electrophoretically pure and active, i.e., hemagglutinating, form.