Bacteriophages are bacterial viruses, which infect bacteria, amplify inside the host, and finally after lysis new bacteriophages are released. Phage production is in most of the cases still traditional, taking place in shaking flasks or on industrial level, in bioreactors as a batch process. Continuous production of phages could represent a valuable alternative. We focused on continuous bacteriophage production in system of two bioreactors connected in series and we tested two versions. The first version consisted of two connected stirred bioreactors in series, representing cellstat. Second version consisted of first bioreactor being stirred bioreactor and the other being a tubular bioreactor. In both versions, the bacteria was cultivated in the first bioreactor without presence of bacteriophages, in second bioreactor infection of bacteria with bacteriophage occured and bacteriophage multiplication was intiated. For bacteria-bacteriophage system we choosed obligately lytic bacteriophage T4 and facultative anaerobic Escherichia coli K-12 as host. Dilution rate in stirred bioreactor have a significant effect on bacteriophage growth parameters: adsorption constant, latent period and burst size, similarly has an important effect also on bacteriophage population growth rate. In studies to determine productivity of continuous bacteriophage production (first version), it was found that there exist dilution rate in the second stirred bioreactor at which the productivity is maximal (for variable and constant physiological state of bacteria), while the trends of concentration of bacteriophages differed significantly. Theoretical analysis was performed to determine influence of variables, the results showed that process parameters (dilution rate and concentration of bacteria) and bacteriophage growth parameters (adsorption, latent period and burst size), have an influence on productivity. Latent period have the most important effect on optimal dilution rate (dilution rate at which maximal productivity is achieved), while latent period and burst size have the most profound effect on maximal productivity. Experiments of second version showed that robust continuous bacteriophage production in a system of two consecutive bioreactors, the first being stirred bioreactor and the other being a tubular bioreactor, can be achieved.