Curcumin, a hydrophobic polyphenol isolated from dried rhizomes of turmeric exhibits diverse pharmacological activities including anti-bacterial.However, the clinical usefulness of curcumin was limited mainly due to low aqueous solubility and stability. The primary aim of the study was to prepare anionic surfactant based curcumin nanosuspension and to assess its in-vitro anti-bacterial efficacy on Escherichia coli in comparison with ethanolic solution of curcumin. Curcumin nanosuspension was prepared by nanoprecipitation method, characterized for the average particle size, span, uniformity, surface area, and surface morphology and assessed for its anti-bacterial activity against gram-negative bacteria Escherichia coli using agar well diffusion method. Prepared curcumin nanosuspension showed an average particle size of about 175 nm, span of about 1.5, uniformity of about 0.8, surface area of about 57 m 2 /g and nanoparticles were spherical in shape. Curcumin nanosuspension have shown significant (P<0.05) anti-bacterial activity against Escherichia coli at various concentrations in comparison with ethanolic solution of curcumin. We conclude that the size reduction of curcumin in nano range has increased the surface area resulting in increased aqueous solubility and reactability of curcumin, which in turn have increased the potency of curcumin nanosuspension.