In this research, the effects of different postharvest treatments on quality and biochemical properties of "Maxibell F1" California Wonder type peppers at green mature stage were determined. In this content, ultraviolet C (UV-C) at 254 nm treatments for 2.5, 5, 10 min and hot water dipping (HWD) treatments for 2 min at 40, 50, 60 degrees C were done respectively. Besides, low density polyethylene (LDPE) and polyvinylchloride (PVC) based modified atmosphere packaging (MAP) applications were materialized. Some quality and biochemical parameters such as flexibility, soluble solids content, weight loss, decay incidence, ascorbic acid content, total chlorophyll content and membrane leakage were assessed after each storage period on peppers. Furthermore, the gas concentrations inside modified atmosphere packages were daily measured. Treated peppers were stored at 6 - 7 degrees C and 90 - 95% RH conditions for 15, 30 and 45 days with two days shelf life at 18 - 20 degrees C respectively. According to the results, storage period affected the quality and biochemical properties. Thus, quality and biochemical properties reduced with prolonged storage period. Furthermore LDPE based MAP, PVC based MAP and HWD at 40 degrees C were found successful in terms of keeping the parameters as mentioned, respectively. The differences between treatments became evident especially after 30 and 45 days storage.