Baculoviruses form a largest and most diverse groups of insect-pathogenic viruses. They are safe for plants, vertebrates and - what is particularly important - for mammals and humans. It was established that these insect specific viruses are widespread in nature among economically important insect pests and they may be applied in pest control programe. Numerous field trials demonstrated usefulness of baculoviruses as viral insecticides, however numerous chemical pesticides with broad spectrum and low cost of production made the natural, viral insecticides economically unprofitable on the market. Only later, at the beginning of the 1980d and 1990s it became apparent that numerous agricultural, environmental and human health problems were a consequence of a widespread use and accumulation of chemical pesticides in the environment. The necessity to develop biologically safe insecticides again focused the attention on the natural, very specific enemies of pest insect. Currently, the research concentrates on lowering the costs of growing baculoviruses in large scale. In addition, attempts have been made to improve the virulence of pesticidal baculoviruses and to expand their host range. These experiments are now in progress in several laboratories. We may expect that in the future a baculovirus genome will be modified by way of changing or deleting its important parts rather than by the expression of additional genes coding for important regulators of insect metabolism.