Gastroesophageal adenocarcinoma (GEA) is a global health issue with a high fatality-to-case ratio and a 5-year overall survival that has only slightly improved. High-throughput molecular profiling has uncovered a profound complexity and heterogeneity in GEA biology, which limits considerably the treatment advances. Liquid biopsy with circulating tumor (ct)DNA analysis could elucidate GEA molecular heterogeneity and provide diagnostic, prognostic and predictive information to guide clinical decision-making. However, only a handful of studies have shown positive results for the application of ctDNA analysis in GEA clinical management. As a result, no comprehensive information is available to date on this continuously evolving topic. Here, we discuss the current state of knowledge, along with promises and challenges related to ctDNA analysis in GEA.