Currently, chemical bifunctional cross-linkers are regarded as promising therapeutic agents capable of affecting cell metabolism. Depending on the nature of the active groups and on the length of their mediating spacer, these cross-linkers have been shown to influence mitochondrial functions, the cell cycle and cell death. The current study was aimed to assay cellular effects of a cross-linker with 'zero'-length spacer, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC). When added to cultures of transformed cells, EDC induced a G2/M blockade followed by cell death. Analysis of the molecular targets revealed that alteration of the cell cycle was caused by EDC-induced interchain cross-linking within double-stranded DNA. Administration of EDC to animals with experimental tumors increased their life span. The analysis of tumor cells from EDC-treated mice showed up-regulation of p21/WAF1, disturbance of tumor cell cytokinesis and, hence, cell death. Thus, both in vitro and in vivo, EDC exhibits cytotoxic activity, which may be of potential therapeutic use.