Poor rural areas in China exhibit the country's highest rates of child mortality, often stemming from preventable health conditions such as diarrhea and respiratory infection. In this study, we investigate the association between breastfeeding and disease among children aged 6⁻24 months in poor rural counties in China. To do this, we conducted a longitudinal, quantitative analysis of socioeconomic demographics, health outcomes, and breastfeeding practices for 1802 child⁻caregiver dyads across 11 nationally designated poverty counties in southern Shaanxi Province in 2013⁻2014. We found low rates of continued breastfeeding that decreased as children developed: from 58.2% at 6⁻12 months, to 21.6% at 12⁻18 months, and finally to 5.2% at 18⁻24 months. These suboptimal rates are lower than all but one other country in the Asia-Pacific region. We further found that only 18.3% of children 6⁻12 months old met the World Health Organization (WHO)-recommended threshold for minimum dietary diversity, defined as consuming four or more of seven specific food groups. Breastfeeding was strongly associated with lower rates of both diarrhea and cough in bivariate and multivariate analyses. As the first analysis to use longitudinal data to examine the relationship between continued breastfeeding and child illness in China, our study confirms the need for programmatic interventions that promote continued breastfeeding in order to improve toddler health in the region.