The study examined the impact of improved cowpea varieties on the income and the food security status of women farmers in Southern Part of Borno State, Nigeria. The specific objectives were to describe the socio-economic characteristics of women cowpea farmers in the study area; identify the changes in income as a result of using improved cowpea seeds by the respondents; analyze the impact of the improved cowpea varieties on the food security status of the respondents; analyze the determinants of technical efficiency of the respondents; estimate the technical efficiency of the respondents in using improved cowpea and identify the constraints associated with the use of improved cowpea varieties. Both primary and secondary data were used for the study. The primary data were collected by use of structured questionnaires administered to 240 participants and 60 non-participants to give a total of 300 respondents who were selected using a random sampling technique. Descriptive statistics, Double Difference (DD), Cost-of-Calorie index and the Stochastic Production Frontier Function were the analytical tools used to analyse the data collected. The results of the descriptive statistics indicated that the respondents were mostly within the age group of 31-40 years implying they are in their active age. Majority are married (68% participants and 75% non-participants), 38% participants and 35% non-participants have household of 6-8 people. An average of 66% participants and 62% non-participants were educated with mean farm sizes of 1.2 and 0.8 hectares respectively. Findings from the Double Difference estimates indicated that the annual income of the participants increased by N143, 495.20 which was higher than that of the non-participants which increased by only
N58, 500.00.This indicates that there was a positive impact on income as a result of using the improved cowpea varieties. The Cost-of-calorie index showed that based on the daily energy level of 2250Kcal recommended by Food and Agriculture Organization, the food security line per adult equivalent per month was N2,743.81 and N2,076.69 for the participants and non-participants respectively. The result also showed that 66% of the participants and 33% of the non-participants were food secure. The Maximum Likelihood Estimates revealed that the coefficients of the production parameters were all positive and significant at one percent. The inefficiency variables affect efficiency in improved cowpea production. The values of sigma square is 3.293 and gamma is 0.997.The estimated mean technical efficiency was 0.7993 which indicates that the improved cowpea farmers could improve their present level of output by 20.4 % given their present resources. The cowpea farmers were constrained by diseases and pests, high cost of labour and inadequate access to markets. It was recommended that policies should be formulated to encourage women farmers in the study area to adopt and sustain the use of improved varieties of cowpea, women farmers in the study area should be given adequate enlightenment on how to control pests and diseases and improved cowpea varieties and other inputs should be made readily available and accessible to the women farmers at affordable prices, on time and in adequate quantities.