In this study, the essential components in aronia fruits grown in Korea were extracted with hot water (WA) and ethanol (EA) to analyze their functional ingredients and their antioxidant and anticancer activities. Aronia leaves, generally discarded as by-products, were analyzed after producing aronia leaf tea through drying (DALT), steaming (SALT), and roasting (RALT). Functional ingredients analyzed included total polyphenol, total flavonoid, and total vitamin C contents. The total polyphenol contents in EA and WA extracts were 40.26 mg GAE/g and 35.45 mg GAE/g, respectively, and the total flavonoid contents were 13.90 mg QE/g and 11.49 mg QE/g, respectively. The total polyphenol and total flavonoid contents of EA were significantly higher than WA. The total polyphenol contents in DALT, SALT, and RALT were 33.67 mg GAE/g, 57.79 mg GAE/g, and 53.16 mg GAE/g, respectively, i.e., in the order SALT > RALT > DALT. The total flavonoid contents in SALT and RALT were 13.29 mg QE/g, 19.30 mg QE/g, 9.98 mg QE/g, i.e., in the order SALT > DALT >RALT. The total vitamin C contents in EA and WA extracts were 71.79 mg/100 g and 59.75 mg/100 g, respectively. The total vitamin C contents in DALT, SALT, and RALT were 11.94 mg/100 g, 15.83 mg/100 g, and 6.72 mg/100 g, respectively, i.e., in the order SALT > DALT > RALT. The possible reason for aronia leaves having a lower total vitamin C content than that of aronia fruits is the loss of vitamin C during the pretreatment of aronia leaves. Antioxidant activity was analyzed using DPPH radical scavenging activity analysis, ABTS radical scavenging activity analysis, and FRAP assay. For all three analyses, EA extracts showed significantly higher antioxidant activity than did WA extracts. In addition, SALT and RALT exhibited significantly higher antioxidant activities than did DALT, and the antioxidant activity increased because of the production of an amino-carbonyl product by the Maillard reaction occurring during the pretreatment of aronia leaves. Cytotoxicity to cancer cells (A-549, HeLa, Hep3B, and MCF-7) was analyzed using MTT and SRB assays, and morphological changes in HeLa cells were observed by injecting WA and SALT extracts into HeLa cells at different concentrations. As per both assays, cytotoxicity to HeLa cells was the highest. The MTT assay revealed that SALT and RALT exhibited high cytotoxicity against HeLa cells, and the SRB assay showed that DALT and SALT exhibited high cytotoxicity against MCF-7 cells, which suggests that aronia fruits and leaves are useful functional food materials for women. In addition, changes in the shape of HeLa cells treated with WA and SART extracts at concentrations of 100?500 μg/mL were observed using an inverted microscope. In the control group, it was observed that the HeLa cells were normally proliferated and tightly attached to the plate, but as the concentration of the WA and SALT extracts was increased, the number of cells significantly decreased. For the quantitative analysis of phenolic compounds (gallic acid, rutin, myricetin, quercetin, and caffeic acid), EA and WA extracts were subjected to HPLC. Here, caffeic acid was not detected, and rutin content was the highest. In addition, gallic acid was not detected in SALT and RALT, and the content of phenolic compounds was higher than that of aronia fruit extracts, except quercetin. The bioactivity of aronia fruits and leaves was verified through this study, and thus, they are expected to be used as functional food materials.