This study aims to explore the ability of oyster (Crassostrea malabonensis) shells as an adsorbent of oil and grease in wastewater. Numerous pollutants can harm our environment. Oil and grease are examples of a pollutant that can cause a serious problem to our environment. Effects of varying amounts of powdered oyster shell and a varying amount of contact time on the sorption capacity of powdered oyster shell on the biosorption using oyster shell were observed. The solutions were then analyzed using Gravimetry (n-Hexane Extraction) (SM 5520 B). The results were used to estimate the adsorbent sorption capacity. The results revealed that a high percentage of adsorption was obtained at a contact time of 24 hours (69.74%) and an adsorbent dosage of 30 grams (79.17%). Generally, the more adsorbent dosage and the longer the contact time, the higher the percentage adsorption of oil and grease.