7-N,8-N-Ethylenemitomycin 8-imines represented by the formula ##STR1## wherein one of the R.sub.1 and R.sub.2 represents carbamoyloxymethyl and another represents hydrogen or both are combined together to form methylene; R.sub.3, R.sub.4, R.sub.5 and R.sub.6 each independently represent hydrogen or C.sub.1-4 alkyl, or R.sub.3 and R.sub.4 may be combined together to represent --(CH.sub.2).sub.n --, wherein n is 3 or 4; and Y and Z represent hydrogen or methyl, provided that when R.sub.1 represents carbamoyloxymethyl and Y represents methyl, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6 and Z are not hydrogen simultaneously, has an excellent antitumor activity.