We have prepared a set of heterocyclic benzimidazole derivatives bearing amidino substituents at C-5 of benzimidazole ring, by introducing various heterocyclic nuclei (pyridine, N-methyl-pyrrole or imidazole) at C-2, and evaluated their antitumor and antiviral activities. The most pronounced antiproliferative activity was shown with compounds 6 and 9, having imidazolinylamidino-substituent. Interestingly, all compounds show noticeable selectivity toward breast cancer cell line MCF-7. The most distinct and selective antiviral activity toward coxsackieviruses and echoviruses was observed with compounds having pyridine ring at C-2. Especially interesting was fairly strong activity of 4 and 8 toward adenoviruses, which could be considered as leads against adenoviral replication.