Selective protein degradation is an efficient and rapid way of terminating protein activity. Defects in protein degradation are associated with a number of human diseases, including potentially DiGeorge syndrome, which is characterised by abnormal development of the neural crest lineage during embryogenesis. We describe the identification of Xenopus Cullin-1, an E3 ubiquitin ligase, and show that blocking the function of endogenous Cullin-1 leads to pleiotropic defects in development. Notably, there is an increased allocation of cells to a neural crest fate and within this lineage, an increase in melanocytes at the expense of cranial ganglia neurons. Most of the observed effects can be attributed to stabilisation of beta-catenin, a known target of Cullin-1-mediated degradation from other systems. Indeed, we show that blocking the function of Cullin-1 leads to a decrease in ubiquitinated beta-catenin and an increase in total beta-catenin. Our results show that Cullin-1-mediated protein degradation plays an essential role in the correct allocation of neural crest fates during embryogenesis.