The focus of work is on the theory of adoption of cellular phone as an innovation and its diffusion and penetration within Pakistani society with a view to testing the famous Roger's theory of diffusion of innovation. The work also testifies role played by advertising in the process of diffusion of innovation. Statistical techniques are used to find out relationship among different variables. The diffusion of innovation theory is formulated with the help of a dedicated survey research method whereby a sample of 200 respondents were approached and researched. Overall findings support the theory of diffusion of innovation.