Abstract: The novel 5'-deoxy-5-fluorocytidine derivatives of formula ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 are hydrogen or an easily hydrolyzable radical under physiological conditions, with the proviso that, at least one or R.sup.1, R.sup.2 and R.sup.3 is an easily hydrolyzable radical under physiological conditions,as well as hydrates of solvates of these compounds have antitumor properties. They can be prepared from compounds of formula I, wherein R.sup.1 is hydrogen or an amino-protecting radical and R.sup.2 and R.sup.3 are hydrogen or a hydroxy-protecting radical or taken together are a cyclic hydroxy-protecting radical.