Description: We had earlier synthesised spin labelled (containing nitroxyl free radical) amino acid nitrosoureas that exhibit in vivo high antitumour activity. Further, it was of interest to study how the replacement of the spin labelled moiety with the cyclohexyamino group in the structure of the spin labelled nitrosoureas would affect their antitumour activity in vivo. Synthesis was achieved by conventional nitrosation according to method described in the literature. Elemental analysis, IR, Mass and NMR spectroscopy were used for confirmation of the new compound structure. Antitumour effect of the new nitrosourea was studied using hybrid BDF1 (DBA/2xC57Bl/6) mice in accordance with the routine methods described in the literature.A new amino acid nitrosourea containing cyclohexylamino moiety was synthesised and its structure was confirmed by elemental analysis, IR, Mass and NMR spectroscopy. Its high antileukaemic activity and antimelanomic effect were shown by in vivo tests. As a whole newly synthesised nitrosourea showed lower general toxicity in comparison with clinically used nitrosourea drug lomustine (CCNU).Results obtained demonstrated that the new compound exhibited in vivo high antitumour activity and low general toxicity. Further investigations with this promising nitrosourea derivative are in progress in our laboratory