A descriptive study to assess the knowledge regarding O.R.S &O.R.S Preparation for diarrhoea among mother of under five children at Nizar village, Surat Methods: An evaluative research approach with descriptive survey and the study was conducted at Nizar village, sample comprised of 50 mothers of under five children sample was selected by convenient. Data was analysed using descriptive and inferential statistics. Result: In demographic data Majority among 50 out of 32(64%) of samples belongs to 2.5years of age group. Majority among 50 out of 49(98%) of the sample were hindu,31(62%) samples education of mother,37(74%) of samples were joint family, 28(56%) samples were above 3000rs, 42(84%)of sample were for source of information. The result of mothers showed 05 (10%) mothers having poor knowledge and 28 (56%) having an average knowledge and 17(34%) mothers having good knowledge. The knowledge score was 21.34, median was 19, mode was 20 and standard deviation 3.35.Conclusion: The result of the study concluded that majority of mothers of under five average knowledge about ORS and its ill effects. There is no association between knowledge scores and the selected demographic variables like age, religion education of mothers, monthly income, type of family, source of knowledge.