Iron is an essential micronutrient whose uptake is strictly regulated in plants. IRON-REGULATED TRANSPORTER 1 (IRT1) is the major transporter for ferrous Fe uptake in A. thaliana. In Fe homeostasis, constitutive turnover is one of the most important characteristics for the regulation of this metal transporter. Although ubiquitination of IRT1 has been proposed as a mechanism of IRT1 degradation, none of specific components have been identified. In this study, we revealed that IRT1 DEGRADATION FACTOR 1 (IDF1) is directly involved in IRT1 degradation through its RING E3 ubiquitin ligase activity.