Acetate-cellulose strips of "Cellogel" type have been shown to be a suitable maintenance medium for performance of isotachophoresis. For immuno-isotachophoresis antigen (from 0.5 to 20 microliter) is applied to a strip of acetate-cellulose film. 1--2 microliter of ampholine solution is placed in front of the antigen zone. All the components present on the strip are made in 0.06 M tris-HCl buffer (pH 6.7), and 0.012 M tris-glycine (pH 8.3) is used as an electrode buffer. Electrophoresis produces migrating Kolraush boundary, which at first is the area of antigen concentration into a narrow starting zone, and then of antigens separation with ampholites. The antigens separated on a cellogel strip are subject to cross-electrophoresis on a film saturated with the respective antiserum, with formation of precipitation peaks for each individual antigen. The method permits to operate with low antigen concentrations since electrophoresis ensures their preliminary concentration and the width of the zones is independent of the time of separation.