Idiopathic thrombocytopenic purpura (ITP) is an acquired organ-specific autoimmune hemorrhagic disease with many immune dysfunctions. Cytotoxic T lymphocyte antigen 4 (CTLA-4) is a T-lymphocyte surface molecule that can down modulate and terminate immune responses. Recently, several studies have confirmed that some polymorphisms of this gene can influence its expression level, therefore speculating that they might be associated with autoimmune diseases. In order to investigate the role of the CTLA-4 gene in ITP, we investigated -318 and CT60 polymorphisms of the CTLA-4 gene in 186 ITP patients and 162 healthy controls through polymerase chain reaction (PCR)-restriction fragment length polymorphism. No significant differences were revealed in genotypes and allele distributions between the patients with ITP and the controls in both sites. Similar results were observed between the two groups when stratified by first onset age and disease course including acute childhood, chronic childhood, acute adult, and chronic adult. In the conclusion, these two single-nucleotide polymorphisms in CTLA-4 are not associated with susceptibility to ITP in a Chinese population.