Synthesis of iron oxide nanoparticles by the recently developed green approach is extremely promising because of its non-toxicity and environmentally friendly behavior. In this study, nano scaled iron oxide particles (α-Fe 2 O 3 ) were synthesized from hexahydrate ferric chloride (FeCl 3 .6H 2 O) with the addition of papaya ( Carica papaya ) leaf extract under atmospheric conditions. The synthesis of iron oxide nanoparticles was confirmed by systematic characterization using FTIR, XRD, FESEM, EDX and TGA studies. The removal efficiency of remazol yellow RR dye with the synthesized iron oxide nanoparticles as a photocatalyst was determined along with emphasizing on the parameters of catalyst dosage, initial dye concentration and pH. Increasing the dose of iron oxide nanoparticles enhanced the decolorization of the dyes and a maximum 76.6% dye degradation was occurred at pH 2 after 6 h at a catalyst dose of 0.8 g/L. Unit removal capacity of the photocatalyst was found to be 340 mg/g at dye concentration of 70 ppm and at a catalyst dose of 0.4 g/L. The synthesized nanoparticles showed moderate antibacterial activity against Klebsiella spp. , E.Coli , Pseudomonas spp. , S.aureus bacterial strains. Although the cytotoxic effect of nanoparticles against Hela, BHK-21 and Vero cell line was found to be toxic at maximum doses but it can be considered for tumor cell damage because it showed excellent activity against the Hela and BHK-21 cell lines.