Objective. To describe and contrast early complementary feeding (ECF) over time in breastfed infants in the Dominican Republic (DR) and Haiti, the two countries that share the island of Hispaniola. Methods. Secondary data analysis was conducted on cross-sectional data from Demographic and Health Surveys administered at four different time-points in both countries between 1994 and 2013. Extracted samples were composed of breastfed infants < 6 months of age whose caregivers had responded to dietary questions on food consumption in the previous 24 hours. Results. Plain water was the most frequently consumed complementary substance in both countries. However, the prevalence of water consumption increased in the DR over time, whereas in Haiti it decreased. Milk (non-breast) use was also common and followed a similar pattern as water over time in the two countries. Expanded use of water and milk in the DR are the major contributors to its drop in exclusive breastfeeding (EBF) rates over time. Whereas in Haiti, a reduction in a broader array of liquids and semi-solids/solids overtime appears to have contributed to its markedly improved EBF rates. Conclusion. Determining contributors to the differential trends in water and milk (non-breast) use between these two countries may identify targets for addressing the persistent gaps in EBF on the island of Hispaniola.