IDH1 R132H mutations occur in approximately 70% of astrocytomas and oligodendroglial tumors. We developed a mouse monoclonal antibody targeting the IDH1 R132H mutation. Here, we show the high specificity and sensitivity of this antibody on Western blots and tissue sections from formalin fixed paraffin embedded tumor specimens. This antibody is highly useful for tumor classification, in detecting single infiltrating tumor cells and for the characterization of the cellular role of mutant IDH1 protein.