The ongoing war in Ukraine has profoundly impacted the Ukrainian scientific community. Numerous researchers have either emigrated or transitioned to alternate professions. For those who remain in research, the destruction of civil infrastructure and psychological stress may dramatically slow down research progress. There is limited knowledge concerning the war's influence on Ukrainian research. This study presents the results of a representative survey of over 2500 Ukrainian scientists. The data suggest that by the Fall of 2022, about 18.5% of the population of Ukrainian scientists fled the country. Notably, these emigrant scientists were amongst the most research-active in Ukraine. However, a significant portion of these migrant scientists are under precarious contracts at their host institutions. Of the scientists who stayed in Ukraine, about 15% have left research, and the others experience a marked reduction in research time. A large number of stayers have lost access to critical input for their research (23.5%) or cannot physically access their institution (20.8%). Finally, should the war stop today, it seems that Ukraine has already lost about seven percent of its scientists. These observations bear significant policy implications. In light of the vulnerable position of migrant scientists, the provision of more and longer scholarships emerges as a paramount concern for this group of scientists. Concerning stayers, institutions across Europe and beyond can offer a host of support programs, such as remote visiting programs, access to digital libraries and computing resources, as well as collaborative research grants.