Müllerian ducts are paired embryonic tubes that give rise to the female reproductive tract; the Fallopian tubes, uterus and upper vagina in humans or the oviduct in birds and mice. As many disorders of duct formation currently lack a molecular diagnosis, there is a critical need to understand the genetic regulation and cellular events of Müllerian duct formation. Most of our understanding of duct development is derived from studies in the chicken embryo, a highly conserved model for avian and mammalian duct formation. We recently conducted a single-cell RNA sequencing study in the chicken embryo, which, for the first time in any species, implicates NOTCH signaling in duct development. This includes the key NOTCH receptors, NOTCH1, and NOTCH2, and the JAG1 and JAG2 ligands. In situ hybridization analysis shows that NOTCH1 and NOTCH2 mRNA is expressed in the Müllerian duct mesenchyme, while the JAG ligands are enriched in the inner duct epithelium throughout duct formation and differentiation. Functional analysis of these genes is currently underway. Activity of the NOTCH pathway is being monitored through in ovo electroporation of HES5 and HES1 reporters. Functional analysis of the pathway is being examined using a potent dominant negative of MAML, which is an obligate co-factor for NOTCH 1 and NOTCH2 signaling in cells. Blockage of NOTCH signaling in the ducts is also being explored using an ENGRAILED-RBPJ fusion construct. Conversely, constitutive activation of NOTCH signaling in the ducts is being induced through the in ovo electroporation of NICD, the active NOTCH Intracellular domain. The results of these functional studies will be reported. This work will shed light on the role of NOTCH signaling in the duct and further our understanding of the molecular basis of Müllerian duct disorders.