Women of child bearing age are vulnerable to food shortage in arid areas and this ultimately affects their nutritional status. Research on these women remains largely unexploited in many parts of the developing countries such as Kenya. The study sought to establish the prevalence of malnutrition and associated factors among women of child bearing age in the Semi arid areas of Keiyo District. .Methods: This was a cross-sectional survey of 335 randomly selected women from three semi arid divisions. Anthropometric measurements of height, weight and mid upper arm circumference (MUAC) were taken. Nutrient intake data was collected using a 24 hour recall questionnaire. A structured questionnaire was used to collect data on socio-demographic information. Data was analysed using SPSS V.16.0. T-test, chi-square and logistic regression were employed in the analysis. P-value of less than 0.05 was considered significant. Results: The mean (SD) age of mothers was 29.9±6.3 years. The prevalence of CED was 44.9%. Compared to RDA, protein, energy, vitamin A, Iron and Zinc intake were significantly low (p<0.05). Vitamin C and Folate intake were significantly higher than RDA. Based on BMI, 39 (12.2%) were underweight, 54 (16%) overweight while 49 (15.9%) were obese. Only 120 (35.8%) of the households ate a diversified diet. Age, marital status, education level, occupation and income level were significantly associated with under-nutrition (p<0.05)