Waste management of dairy products is an important topic for both economic and environmental aspects. In order to remove or reduce the harmful effects of carbon black used as a filler material, the effects of polymers obtained by using some biological wastes such as shelf-life passed milk instead of carbon black on the physical and mechanical properties of ethylene propylene diene monomer (EPDM) rubber have been investigated. Moving Die Rheometer and Soxhlet extraction tests were applied to the obtained compound and the results were evaluated. MDR test results showed that the scorch time of the samples increased by 10% SP filler, and Soxhlet test results were in line with MDR test. Mechanical analysis showed that the addition of casein polymer improved the elongation at break values of the samples. The tests were concluded that the best resulting sample is 10% SP. FTIR result shows that the casein polymer is chemically bonded to the EPDM rubber. The results showed that the prepared bio-based filler could be used as an alternative and non-hazardous filler.