Objective To evaluate the efficacy of protein A immunoadsorption on myasthenia gravis. Methods A total of 24 myasthenia gravis cases were divided into two groups: the treatment group (n=12) and the control group (n=12). Patients in both groups were treated with the traditional therapy, but those in the treatment group received protein A immunoadsoption 3 times per week for 4 weeks. Serum immunoglobulins of IgG, IgA and IgM, complements of C3 and C4, and antibodies against nicotinic acetylcholine receptor were determined before and after the treatment. The efficacy of protein A immunoadsorption on myasthenia gravis patients was evaluated by a scoring system based on physical examinations. Results The overall rate of effectiveness was 91.67% in the treatment group and 75% in the control group (p<0.05). The numbers of patients showing complete recovery, significant recovery, improvement, response and no response were 5, 2, 3, 1 and 1, respectively, in the treatment group, and were 2, 2, 2, 3 and 3, respectively, in the control group. Serum IgG, IgA and IgM and antibodies against the nicotinic acetylcholine receptor decreased more remarkably in the treatment group than in the control group (p＜0.01). Conclusions Protein A immunoadsorption significantly lowered serum IgG, IgA, IgM and antibodies against the nicotinic acetylcholine receptor, and shortened the disease course in myasthenia gravis patients. Therefore, it is an effective method and can be used in association with the traditional therapy for myasthenia gravis patients.