Abstract: Calculations of Millimeter-wave rain scattering parameters are made at 16, 19.3 and 34.8 using spherical and oblate spheroidal rain models. Computations are made at angle of incidence of 0 and 90 ° for the oblate spheroidal rain model. The characteristic of the difference between the two models with rain rate are studied at incidence angle of 0 ° to allow us determine their suitability in a tropical environment. Some propagation parameters are evaluated using the Indian lognormal and Marshall and Palmer (MP) Drop Size Distributions (DSD’s). Marshall and Palmer DSD model could underestimate rain-induced attenuation at all the frequencies in the rain rate range of 0.25≤R<50 mm h-1 and overestimate specific phase shift at rain rate R>100 mm h-1 if adopted for radio wave propagation prediction on tropical path. However, Indian data compare well with MP at rain rate in the range 50≤R≤100 mm h-1. Similarly, spherical rain model could underestimate the specific attenuation with a maximum margin of 3.4 dB km-1 at 34.8 GHz and specific phase shift of 15.7 ° km-1 at 16 GHz, both at rain rate of 150 mm h-1. The empirical scaling relationship between the radar reflectivity η and rain rate R (η = aRb) are derived for the Indian DSD and the coefficients a and b compare well with those of Aydin and Lure.