Bovine serum albumins show a short-range attraction and a long-range electrostatic repulsion amongthem and these interactions are modified depending upon the solution pD and different dissolved coun-terions in the solution. Small angle neutron scattering study shows that for equal mono-valent (Na+) anddi-valent (Ni2+) ion concentrations, both the attractive and repulsive interaction decreases with loweringthe solution pD toward the protein isoelectric point, however for the tri-valent (Fe3+) ion attractive inter-action increases and repulsive interaction decreases. Interaction variation for the equal ionic strength ofthe three different valent ions becomes prominent as the pD decreases toward the isoelectric point.