The study investigated the prevalence of postpartum depression (PPD) among nursing mothers attending primary health centers in Alimosho Local Government Area, Lagos State. Two research questions and hypotheses werepostulated, and the descriptive survey research design was adopted. The population of this study comprises of all nursing mothers attending primary health centers in Alimosho Local Government Area, Lagos State. The purposive sampling technique was used to select the nursing mothers in the five primary healthcare centres in Alimosho Local Government Area. The sample for this study comprises of two hundred (200) nursing mothers attending primary health centers in Alimosho Local Government Area.  A self-developed structured questionnaire was used in this study. The self-developed structured questionnaire was in two different sections. Section A found out about the demographic information of the respondents while Section B attempted to get the respondents views to the questions using the 4-point Likert scale. Findings from the study revealed that Age plays a crucial role in the prevalence of postpartum depression among nursing mothers. Certain risk factors contribute to postpartum depression in nursing mothers, cultural norms and societal factors relate to and have an impact on postpartum depression in nursing mothers. Also, it was revealed that postpartum depression has severe consequences on maternal wellbeing as well as infant care, some of these consequences include but are not limited to difficulty bonding with their baby, feelings of guilt and worthlessness in mothers, difficulties breastfeeding and thoughts of self-harm or suicide. Based on the findings in the study, it was recommended that: the government should Improve access to mental health services in Alimosho Local Government Area, specifically targeting younger mothers who may be at a higher risk of postpartum depression. Also, nursing mothers should foster open communication with support network, including their partner, family, and friends. It was also recommended that health educators should advocate for governmental policies that prioritize maternal mental health and allocate resources to support mental health programs within Alimosho Local Government Area.