A galactose- and N-acetyl-D-galactosamine-specific lectin (Viscum album L. var. coloratum agglutinin, VCA), which is known for its anticancer activity, was isolated from Korean mistletoe. This study reports a microarray analysis of the effects of VCA on an activated human T cells under various times and concentrations. A total of over 3000 genes were identified whose expression levels were significantly altered against controls after treatment with VCA and anti-CD3/CD28 antibody stimulation on human T-cells over an 8 h period. An analysis of the gene expression profile induced by VCA following incubation in human T cells revealed the activation and inhibition of genes involved in a wide range of immune functions in line with the broad mechanisms of action of VCA. These functions include cytokine gene expression, cell adhesion, cell motility, cell growth and maintenance, cell death, and the response to stress and to external stimulus. This report is aimed at providing the mistletoe research community with a robust database on which further studies could be built.