Proceedings of Tanzania Veterinary Association Annual Scientific Conference, AICC Arusha, 5 – 7th December, 2018: 9-15Phages are bacterio-specific viruses. Involved in the origin of life and evolution, constituting a major part of the biosphere, they are promising as a sustainable, ecological and intrinsically cheap antibacterial. They have been proposed as alternatives to antibiotics for many antibiotic resistant bacterial strains. Phages can be used as biocontrol agents in agriculture and petroleum industry. Moreover phages are used as vehicles for vaccines both DNA and protein, for the detection of pathogenic bacterial strain, as display system for many proteins and antibodies. Bacteriophages are diverse group of viruses which are easily manipulated and therefore they have potential uses in biotechnology, research, and therapeutics. The aim of this review article is to enable the wide range of researchers, scientists, and biotechnologist who are putting phages into practice, to accelerate the progress and development in the field of biotechnology. Details given above give a glimpse of the large range of applications of phages in the field of biotechnology and medical science. There is the hope that phages could be useful to humans in many ways. By making a cock tail of phages it would become easy to treat a wide variety of bacterial infections that are otherwise resistant to the latest generations of antibiotics. Due to the rapid progress in the fields of biotechnology and molecular biology it is hoped that these entities (phages) which are present abundantly in the biosphere could answer many questions human beings are having.