In recent years, many researchers have shifted their attention away from synthetic bioactive compounds to naturally existing ones for the purpose of novel therapeutic drugs. Such studies focused on the bioactive compounds from plants or animal sources including marine bivalves. Anadara uropigimelana is one of the most abundant marine bivalves along the coastal zones of the Mediterranean Sea, Port Said, Egypt.  In the present study, live samples of A. uropigimelana (Au) were collected from the intertidal zones during winter to avoid elevated water temperature and gametogenesis during summer. GC-MS analysis was used to identify and characterize the bioactive compounds in Au extract. The protein content, flavonoid, and antioxidants of the Au extract were assessed. Its DPPH radical scavenging activity and its cytotoxicity (MTT assay) against the human breast cancer cells (MCF-7) were performed. Twenty-eight compounds were identified with a variety of referenced pharmacological activities. The MTT results showed that Au extract has a cytotoxic effect against MCF-7 (IC₅₀ value was 0.579 mg/ml after 72 h of treatment). Au extract exhibited higher DPPH scavenging activity, with IC₅₀ of 59.61 µg/ml than that of the ascorbic acid. The present results indicate that Au extract showed rich content of flavonoids and proteins with appreciated antioxidant activity and cytotoxic effect against a representative cancer cell model. The present study spotlighted one of the ecologically neglected marine bivalves, that offers a valuable tissue extract, which could be beneficially used as a natural source of bioactive compounds with its considerable content of protein, flavonoids, and antioxidants.