Background Type 1 diabetes has been recognized as an organ specific autoimmune disease owing to the immune destruction of pancreatic islet β cells in genetically susceptible individuals.In both human and rodent models of type 1 diabetes, such as nonobese diabetic (NOD) mice, biobreeding rats, the disease has a distinct stage characterized by immune cells infiltrating in the pancreas (insulitis).The major populations of infiltrating cells are macrophages and T lymphocytes.Therefore, immune cell infiltration of pancreatic islets may be a crucial step in the pathogenesis of type 1 diabetes.Monocyte chemoattractant protein-1 can specifically attract monocytes in vivo.Interferon induced protein-10 has chemoattractant effects on the activated lymphocytes.In this study, we analysed the expression of monocyte chemoattractant protein-1 in the pancreas of mice and interferon inducible protein-10 mRNA in the pancreas of NOD mice, and discussed their possible role in the pathogenesis of type 1 diabetes.Methods The immunohistochemical method and immunoelectronmicroscopy were used to evaluate the expression of monocyte chemoattractant protein-1 in the pancreas of NOD mice and BALB/c mice.RT-PCR was used to evaluate the expression of monocyte chemoattractant protein-1 and interferon inducible protein mRNA in NOD mice.Results Monocyte chemoattractant protein-1 was positive in the pancreas of NOD mice, whereas negative in the pancreas of BALB/C mice.RT-PCR showed that monocyte chemoattractant protein-1 and interferon inducible protein-10 mRNA could be found in the pancreas of NOD mice.Immunoelectronmicroscopy demonstrated that monocyte chemoattractant protein-1 was produced by β cells and stored in the cytoplasm of the cells.Conclusions Pancreatic islet β cells produce monocyte chemoattractantprotein-1 in NOD mice.Monocyte chemoattractant protein-1 may play an important part in the pathogenesis of type 1 diabetes by attracting monocytes/macrophages to infiltrate pancreatic islets.