Using the Bayley Scales of Infant and Toddler Development-III (BSID-III), we examine the rates of developmental delays among children aged 0–3 years in four major subpopulations of rural China, which, altogether, account for 69% of China's rural children and 49% of children nationwide. The results indicate that 85% of the 3,353 rural children in our sample suffer from at least one kind of developmental delay. Specifically, 49% of the children have cognitive delays, 52% have language delays, 53% have social emotional delays, and 30% have motor delays. The results suggest that these high rates are due to two main factors in the parenting environment. The first is micronutrient deficiencies, which are reflected in a high prevalence of anemia (42%). The second is an absence of interactive parenting inputs, such as storytelling, reading, singing, and playing. Although we find these inputs to be significantly and positively associated with better developmental outcomes, only a small share of caregivers engage in them. With this large and broad sample, we show that, if China hopes to build up enough human capital to transition to a high-income economy, early childhood development in rural areas urgently requires more attention.