In this thesis we report on molecular dynamics simulations of phase separation of simple and complex binary liquids in sheared and non-sheared systems. The separation of milk into liquid whey and solid curd is a very common example of phase separation observed in daily life. The phenomenon finds its application in various fields of science and technology, ranging from metals, semiconductors, superconductors to simple and complex fluids such as polymers, surfactants, colloids, emulsions and biological materials. The principles driving the phenomenon of phase separation are very fundamental in nature, i.e. interaction difference between like and unlike molecules, making it an interesting problem to study. The aim of our study is to enhance the understanding of the dynamics and rheology of the phenomenon of phase separation.