Numerical simulations of light scattering by irregularly shaped bacteria are carried out using the T-matrix method. A
previously developed T-matrix code for the study of light scattering by randomly oriented non-spherical particles is used
for the current purpose and it is validated against Mie-theory using coccus. Simplified particle shapes of spheroids and
cylinders for simulating scattering by irregularly shaped bacteria are studied. The results for the angular distributions of
the scattering matrix elements of B.Subtilis at wavelength 0.6328μm are presented. Their dependence on shape and
model are discussed. Analysis suggests that spheroids perform better than cylinders for B.Subtilis. Calculations of the
scatter matrix elements to determine bacteria sizes as well as shapes may be an accurate method and may be used to
determine what the bacteria are.