The heart is the first organ to develop in the human embryo, first beating around week 3 of gestation and resembling the adult four-chambered heart by the end of month 2. The successful development of the heart is critical to sustain life. The dysregulation of heart development leads to congenital heart defects (CHDs), which affect about 1% of births each year. In the majority of cases the exact cause is unknown. Specifically, the cellular and molecular dynamics of heart development that are impacted in CHD remain unexplored. Genome sequencing studies have identified multiple genetic variants that correlate with CHD but the functional validation is challenging and a major bottleneck. Animal models, like mice and zebrafish, can help answering these questions but it is becoming more and more apparent that not all developmental processes are conserved between these animals and humans. There is therefore an unmet need for new models to test genetic variants and to understand the mechanisms of CHD in a human context. To address this challenge, we are using the human pluripotent stem cell-based gastruloid model, that recapitulates human development including gastrulation and axis formation, and extending it towards early stages of heart development. We expect that these cardiogenic gastruloids will provide novel insights into human heart development. What is more, we aim to use them to model a variety of CHDs, aiding in the study of the disease mechanisms and identification of potential treatment targets.