Maternal depression significantly contributes to global mental disorders and disease-related disability in womenof reproductive age, predominantlyin developing nations, causing detrimental effects on families.We soughtto determine the prevalence of maternal depression in women with children younger than5 years and its contributingfactors.METHODOLOGYWe conductedacross-sectional studyfrom 24thApril to 5thMay 2023,among 354 women who had children below 5 years in Kianda village, Kibrainformal settlementsin NairobiCounty.We used the Patient Health Questionnaire-9 to measure maternal depression. Using the Household Food Insecurity Access Scale and structured questionnaires we gathered the participants’ foodsecurity statusand sociodemographic information, respectively. We measured the participants’ weight and height to determine theirnutritional status. We used descriptive and inferential statistics to calculate the prevalence of depression and identify associated factors.RESULTSThe prevalence of maternal depression was 30.7%. Underweightmothers were 11 times more likely to suffer depression than those withnormal weight(p=0.004). Lower education predisposed mothers to depression by 58% more than higher education(p = 0.043). Fulltime housewives were twice as likely to have depression than those with an occupation(p=0.038). Households with moderate food insecurity were 23% more likely to have depressed mothers compared to households with food security(p <0.001).CONCLUSIONMaternal depression was prevalent in Kianda village, Kibra informal settlement. Maternal depression was linked to underweight, low educational attainment, full-time housewifery, and food insecurity. Maternal depression screening in the community, along with referrals as needed, can benefit women's mental health. Furthermore, focused interventions to improve undernutrition, socioeconomic disparities, and household food security could significantly reduce maternal depression