Abstract: The total cell proteins obtained from the trophozoites of four Giardia lamblia isolates, of which three were isolated from China (C₁, C₂, and C₃ ), and one from America(CDC), were studied by using an isoelectric focusing technique.It was shown that each of the three domestic isolates produced identical banding patterns,of which bands rang from pl 3.6 to 8.3.The banding pattern of the Anierican isolate was different from those of the Chinese isolates,which produced two adclitional new bands.The two distuict bands located at pI 7.1 and 7.8 respectively.The present study shows that geographical separation may be one of the reasons which causes difference between Giardia isolates from different geographical regions.

Key words: Giardia lamblia, total cell proteins, isoelectric focusing