Background Child birth intervalis the length of time between two successful live births.Shorter child birth interval among women of reproductive age is a serious global public health challenge. It is associated with low birth weight, child malnutrition, and child mortality.There is a general dearth of literature on this subject in Zambia. Therefore, the aim of this study was to establish the determinants of second child birth interval among women. Methods A cross-sectional study involving 100 women of reproductiveage group in Lusaka province. The participants were purposively and convenientlyselected. A pre tested structured questionnaire was used to collect the data. The key variables in the data were age, marital status, educational level, tribe, income. The data from the questionnaires were summarized into a Microsoft excel sheet, and cleaned for errors and duplications.Thereafter the excel sheet was exported to Stata version 14.2 for analysis.Kaplan-Meier and Cox regression analysis wereapplied. Results The p-value for age was 0.00 which was statistically significant. Within the age group 18-25 years the average second birth interval was 23 months. In the age group 26-44 years, the average second birth interval was 42 months. The reported p-value for income was 0.049 which was significant. The results also showed that those with income between K0-K350 had an average second birth interval of child of 27 months. Those with income of K3500-K16000, had an average second birth interval 69 months. Women in urban areas had a longer second birth interval than those in rural areas. Conclusion Age, income and location were found to be significantly associated with the incidence of a second birth. A lot of awareness activities on birth control are therefore recommended among young, low income and rural women.