The Fractional Fourier Transform (FrFT) is a generalization of the ordinary Fourier transform. The ordinary Fourier transform and related techniques are of importance in various different areas like communications, signal processing and control systems. In fact, the FrFT has already found many applications in the areas of signal processing and communications. The success of FrFT in its application has promoted the development of other kinds of fractional transforms like fractional Hartley transform, fractional Hadamard transform, fractional cosine transform and fractional sine transform (FrST). Fractional cosine transform is the extension of cosine transform and it has been widely used in domain of digital signal and image processing. In this paper convolution theorem for generalized two dimensional fractional cosine transform is proved.