The influence of the type of plasticizer and its concentration on the rheological behaviour of plastisols made from several commercial resins during the gelation and fusion processes has been studied. The use of different concentrations of plasticizers as well as plasticizers with different compatibilities has allowed the observation of relevant differences in the behaviour of the elastic and viscous moduli in plastisols with low concentration of plasticizer as well as in plastisols prepared with plasticizers having higher compatibility with PVC. In addition, scanning electron microscopy has been used in order to obtain a better understanding of the gelation and fusion processes.