Insect viruses are biological control agents that cause their illness or dead by infecting the insects. Recently, these viruses have great interest at modern biotechnological applications. Insect viruses that have high host specificity, have been used against various agricultural and forest pest as an alternative to chemical pesticides. Studies done with these viruses have been used as model for high organizational organisms. Many genes that has industrial, agricultural, medical and economical importance have been produced at great amounts at expression systems developed from these viruses. Also, recently these viruses are being used as gene therapy vector. At this review paper, we will pay attention on subjects especially at insect viruses, and potential of the usage of baculoviruses at various biotechnological studies.