Background: The use of medication during pregnancy is very common. Medication safety has been a great concern among pregnant women and is highly influenced by women's medication information literacy (MIL). There have been few studies focusing on MIL of pregnant women in China. The misuse of medication during pregnancy may impose on risks on pregnancy. Objectives: The focus of this study was to investigate the MIL of pregnant Chinese women and to identify influencing factors. Methods: Convenience sampling was used following the distribution of a researcher-designed questionnaire to pregnant women at obstetric clinics. A scale was developed to evaluate participants' MIL which included medication information needs, medication information sources, medication information quality discrimination, medication information source awareness, and medication-taking behavior. Demographic characteristics of participants, health status and medication use during pregnancy were also collected. Results: Questionnaires were completed by 570 participants, yielding a 99% response rate. The total score on the Pregnant Women's Medication Information Literacy Scale ranged from 47 to 96 with a mean score of 74.25 +/- 8.22. A total score of 80% or higher indicated the participants' have sufficient medication information literacy which was achieved by 28.2% of the sample. Rate of participants who have sufficient MIL on subscale domains were: medication information needs (76.6%), medication-taking behavior (49.9%), medication information source awareness (26.8%), medication information quality discrimination (17.3%) and medication information sources (15.3%). Significant differences were found in the MIL of participants related to education level, location of residence, occupation, household income, age, weeks of gestation and medication history (p < .05). Binary logistic regression analysis indicated that education, income level, location of residence, occupation, and weeks of gestation affected participants' MIL. Conclusions: The overall MIL is low among pregnant Chinese women, which suggests a need for healthcare professionals focusing on medication safety teaching to pregnant women. Interventions by health care professionals in obstetric clinics that promote MIL and prevent adverse events related to medications should be individualized based upon pregnant woman's education level, financial resources, community of residence, occupation and week of gestation.