The effect of two elastomers and a newly developed plastomer on rheological, mechanical, and thermal properties of their blends with a commercially available recycled polyethylene were studied. The results show effective improvements in engineering properties of the recycled polyethylene (PE). Low percentages of these modifiers give rise to higher elastic properties of the blends. Addition of all modifiers resulted in decreases in crystallinity and in melting point of the blends. Depending on modifier type the intensity of the changes was different. It is concluded from infrared spectra of the blends that no chemical interaction occurs during melt mixing of the ingredients. These improvements are attributed to morphological changes and physical interactions between modifiers and PE matrix. In melt state, as the modification percentage increases and depending on the nature of modifier, the resulting blends show different rheological behavior: EPDM447 constantly increases the viscosity and elasticity of the corresponding blends; EPDM541 is almost ineffective; and EXACT (TM) 4041 decreases and then increases these properties, depending on its concentration in the blend. The results presented in terms of weighed relaxation time spectra show different behaviors depending on the additive. For all modifiers, the 7% modification was always found to have the most pronounced effect on almost all properties of the blends. It was also found that EPDM447 shows the best effects on different properties of the recycled PE.