Regulatory CD4+ CD25+Foxp3+ T cells are involved in the regulation of immune response and inhibit protective antitumor immunity. Celiac disease (CD), a food gluten-sensitive enteropathy, is considered a T-cell-mediated autoimmune disease and is generally associated with an overall increased risk of cancer in CD patients. We observed a higher percentage of circulating CD4+CD25+Foxp3+ T cells and an increased Foxp3 expression in CD4+CD25+ T cells from untreated than from treated CD patients. In co-culture, CD4+CD25+ T cells from both treated and untreated CD patients significantly suppressed the proliferation of autologous CD4+CD25(-) T cells similarly to values in healthy subjects. Our study suggests that Treg proportion and Foxp3 expression in circulating CD4+CD25+ T cells could justify the increased global risk of malignancy in CD population and support the efficacy of lifelong gluten-free diet in the reduction of the cancer risk.