Protein kinase C (PKC) is a key enzyme for neural plasticity. Our recent studies in Zebra Finches (Taeniopygia guttata) and Bengalese Finches (Lonchura striata var. domestica) strongly suggested to us that PKC is closely related to the plasticity for the song learning and alteration. In the present study, we examined the distribution of the isoforms of PKC in the male Zebra Finch brain, with an especial focus on the song control nuclei, using antibodies against the classical PKC isoforms (PKCα, β1, βII and γ). We determined the differential intracellular, cellular and regional distributions of the PKC isoforms in the avian brain. These comparisons of the distributions of the PKC isoforms give us further insights into the molecular mechanisms of avian song learning and maintenance.