The distribution and variability of particulate back scattering coefficient (b_bp) in the Godavari basin are reported for the first time using in situ measurements. A coastal cruise was conducted in the coastal waters Off Kakinada and Yanam along the East coast of India, from 2–9 March 2012. Hyperspectral underwater radiometer was used to collect the in situ bio-optical data as function of wavelength in 21 sampling stations from the coast (approx10 m) to toward the open ocean (appprox150 m). Data from these sites exhibits two orders of magnitude in b_bp and covered the typical coastal and estuarine waters. The b_bp at a single wavelength, i.e., 700 nm was measured with the embedded echo-VSF (Wetlabs) series sensor. In this letter, an attempt was made to: 1) describe the variability of particle b_bp of estuarine coastal system using in situ measurements; 2) model the b_bp from Quasi Analytical Algorithm (QAA) and verify its accuracy by comparing with in-situ measurements of b_bp; and 3) examine the relationship of b_bp and chlorophyll -a concentration in the coastal system. A significant relationship was observed between the in-situ and model derived b_bp values. The in-situ measured b_bp values vary from 0.01 to 0.065 m?1 in this region. The relationship between chlorophyll-a concentration and the b_bp has been studied. The large spread in the scatter in the chlorophyll Vs. in-situ b_bp infers that chlorophyll-a is a poor predictor of b_bp. The relationship between chlorophyll-a concentration and the b_bp shows an inverse relationship for the Godavari Estuarine waters.