Microtubule-associated protein 2 (MAP2) plays a role in microtubule assembly in neuronal processes. Although MAP2 expression was reported in injured astrocytes more than thirty years ago (PMID: 1692628), this protein is widely used today as a neuron-specific marker in studies of the central nervous system. Here we report in vitro MAP2 expression in rat primary astrocyte cultures, using immunostaining with two independent antibodies. We also confirmed prior reports of in vivo MAP2 expression in GFAP+ astrocytes surrounding the needle track following stereotaxic infusions of the mouse brain. In primary astrocyte cultures evaluated by immunocytochemistry and immunoblotting, astrocytes expressed a low-molecular mass isoform of MAP2 (~75 kDa) but not the neuron marker NeuN. Control primary cultures containing neurons displayed two isoforms of MAP2 (~75 and >250 kDa) as well as abundant NeuN expression. Treating astrocyte cultures with the oxidative toxicants paraquat and hydrogen peroxide or increasing the passages of the astrocytes did not raise MAP2 expression levels by immunoblotting. Increasing the cell plating densities in primary astrocyte cultures or applying the proteasome inhibitor MG132 also did not affect MAP2 or GFAP expression in primary astrocyte cultures by immunocytochemistry. Thus, additional MAP2 expression may not be observed in cultured GFAP+ astrocytes, as they have already undergone intense gliosis. These findings have significant implications for the common use of MAP2 as a marker of neurons.