Our objective was to determine the effectiveness of an intervention that incorporated education about the "six cleans" with the use of a clean delivery kit in preventing cord infection and puerperal sepsis. A stepped-wedge, cross-sectional study was conducted in 10 surveillance sites across two rural districts of Mwanza Region, Tanzania. A total of 3262 pregnant women between the ages of 17 and 45 years were enrolled in the study. Village health workers administered questionnaires to each mother at 5 days postpartum and inspected the infants' umbilical cord stumps for signs of infection. Newborns whose mothers used the delivery kit were 13.1 times less likely to develop cord infection than infants whose mothers did not use the kit. Furthermore, women who used the kit for delivery were 3.2 times less likely to develop puerperal sepsis than women who did not use the kit. Women who bathed before delivery were 2.6 times less likely to develop puerperal sepsis than women who did not bathe, and their infants were 3.9 times less likely to develop cord infection. Single-use delivery kits, when combined with education about clean delivery, can have a positive impact on the health of women and their newborns by significantly decreasing the likelihood of developing puerperal sepsis or cord infection.