A simple, sensitive, rapid, cheap and reliable UV spectrophotometric method for the quantitative determination of cefoxitin in powder for injection dosage form has been developed. The UV-spectrum has scanned between 200 nm and 400 nm, and 231 nm is selected as maximum wavelength for absorption. This method obeys Beer's law in the range of 10 - 50 mu g/mL with correlation coefficient of 0.999. The accuracy (98.71-99.36%) and precision results are found to be satisfactory, and hence this method can be used for routine analysis of cefoxitin sodium in sterile dosage form. The method is then validated according to the Q2 R1, International Conference on Harmonization (2005) guideline. Stability of the drug is studied by hydrolysis, oxidation and effect of heat. It is found that the drug is more degraded in water when compared to other stress condition.