The nitrogen laser (λ = 337.1 nm) was documented to have photosensitized inactivation of bacteriophages P1 and phage A havingEscherichia coli andSalmonella typhi as their respective hosts. Methylene blue and crystal violet had a direct virucidal effect whereas toluidine blue revealed accentuated lethal effect on photosensitization with N2 laser for both of the bacteriophages taken in the study. The other dyes such as congo red, neutral red, auramin O and safranine showed differences in their virucidal activity among the two bacteriophages. However, malachite green did not show any change for the two viruses both by itself and on irradiation with the laser. A possibility of photosensitizing effect of N2 laser for the therapy of viral infections needs to be explored.