In the present paper, experimental investigation and continuum mechanical modeling of Mullins effect in swollen elastomers, due to exposure to palm biodiesel, under cyclic loading conditions are addressed. To this end, the nature of Mullins effect in both dry and swollen elastomers is explored and compared. It is found that swelling reduces Mullins effect. Based on experimental observations, in order to account for swelling in the modeling of Mullins effect, two constitutive equations widely used in literature are considered and phenomenologically extended: Continuum Damage Mechanics model and Pseudo-Elastic model. The efficiency of the two extended models are assessed and perspectives for further development are drawn.