Background Various etiologies that contribute to the loss of pregnancy have been proposed. Despite the lack of established and uniform screening methods for recurrent pregnancy loss (RPL), there are several factors considered to be definite (or probable) causes of RPL. Data describing the etiological characteristics of RPL consist almost entirely of Caucasian populations. As we were interested in the Chinese population, the goal of this study was to determine the etiological characteristics of RPL in the Chinese patients.Methods The study was performed retrospectively by analyzing 1122 women with RPL. Patients were divided into three groups according to their number of pregnancy losses. Diagnostic tests included the following 9 critiria: parental genetics, uterine anatomy, autoimmune factors, alloimmune factors, thrombophilic factors, endocrine parameters, genital infection, toxoplasma, rubella, cytomegalovirus, herpes (TORCH) titers and RH blood groups. The criteria for abnormal results were defined before diagnosis.Results We found that 87.1% (977/1122) patients had no more than 3 abnormal aspects, and the proportion of total abnormal results was similar among groups. The prevalence of abnormal results for each test did not differ among groups,except in the cases of parental genetics, uterine anatomy and presence of mixed lymphocyte reaction blocking antibodies (MLR-Bf). Absence of MLR-Bf, as well as abnormally increased levels of CD3+CD19+ and CD56+CD16+ cells, was commonly detected in Chinese RPL patients.Conclusion Immunological disorders play an important role in RPL among Chinese patients.