Placental mesenchymal dysplasia (PMD) is a rare placental disorder that may coexist with a normal fetus but is frequently associated with fetal growth restriction, fetal demise, prematurity, and Beckwith-Wiedemann syndrome, as well as with various fetal anatomical and vascular anomalies. In this case, ultrasonography performed at 14 weeks of gestation revealed multiple, variable sized cysts in the placenta along with a morphologically normal fetus. Serial sonographic examinations found that the fetus became small for gestational age and had a dysplastic right kidney. After delivery at 33 weeks of gestation, histopathologic examination of the placenta showed enlarged, hydropic stem villi with cavity formation and absence of trophoblastic proliferation and pseudoinclusions, all of which were consistent with PMD. Neonatal abdominal ultrasonography showed multiple cysts in the right kidney consistent with a multicystic dysplastic condition. This appears to be the first case of PMD associated with fetal multicystic dysplastic kidney.