Mathematical modelling of infectious diseases is the research work that focuses on the population dynamics of infectious diseases. Here the work starts with basics of the epidemic modelling. The models are formulated for various infectious diseases like malaria HIV TB influenza typhoid etc. Bifurcation analysis is done for each model in order to identify the most crucial parameters responsible for the disease spread. The work is carried out under the guidance of Prof. (Dr.) Nita H. Shah Gujarat University.