This was a cross-sectional descriptive survey and the objectives were to find out the nutritional status and associated factors of children under-five years in Mwanamukia of Kasarani Sub-County of Nairobi County. Structured questionnaire was used on demographic, socio-economic and child caring practice. Anthropometric measurements were used. 43% severely stunted and 27%  normal. 43% underweight, 26% normal. Severe wasting 20% 50.3% normal. Children age 36-47 months stunted (<-3 Z scores) than younger children, children aged 0-6 months had normal nutritional status. Low dietary diversity were achieved by children under-five (58% (<4 food groups), 23% medium scores (4-8 food groups), 19% high scores (6-8 food groups).  Most consumed cereals (79%), legumes (10%), and meat (0.2%).  (82%) consumed one meal per day, (6.6%) three meals/ day. Risk of stunting 5.343 times higher in children who did not meet minimum dietary diversity.  Risk of stunting was higher (OR=2.421 Ci =1.340-10.346 PV= 0.003).  Education 44.6%, 8% illiterate, 34.6% 0’level education, 0.8% University. Low dietary diversity stunted P.V =0.003. Occupation 28.6%, small businesses, and 21.2% farmers. Monthly income KES 11000-20000, lowest KES 1000-10000 per month, 68% had KES 30000/ month. There was no significance difference between nutritional status and household socio-economic status, age of mothers, educational level and occupation PV=0.003. The study shows there is high prevalence of stunting and under-weight in children. In conclusion there was low dietary diversity and low food consumption frequency. Stunting had statically significant association with low dietary diversity and underweight had a statistically significant relationship with household size.