Background: Health-care-associated infection (HCAI) is a big challenge in both low-and high-income countries. Around childbirth, infection is among the main causes of maternal and perinatal morbidity and mortality. Appropriate hand hygiene practice is a simple and cost-effective way of reducing HCAIs. This study aimed to assess the baseline performance and knowledge of proper hand hygiene during caesarean sections and the impact of interventions guided by a criterion-based audit at a tertiary health facility in Tanzania. Methods: A noncontrolled, before-and-after intervention study, guided by a criterion-based audit, was carried out. A criterion based checklist was used for direct observations of hand hygiene performance during cesarean section. A self-administered questionnaire was used to assess knowledge on infection prevention. Performance was compared before and after a half-way intervention. Results: At baseline, low-quality hand hygiene performance was observed. Significant improvements of hand hygiene performance were observed for a number of criteria. Long nails: performance reduction from 15 (25%) to 3 (5%) (P=.04), polished nails: from 11 (18%) to 1 (2%) (P=.04), a score increase in hand wash with water from 43.8 (73%) to 60 (100%) (P=.001). Postoperatively, correct glove removal increased from 20 (33%) to 37.8 (66%) (P=.01). Alcohol-based hand rub use increased from 2 (3%) to 21 (35%) (P=.001). The number of health-care workers who did not wash hands after procedure with either water or alcohol-based hand rub reduced from 35 (58%) to 10 (17%) (P=.001). After the intervention, poor knowledge among health-care workers reduced from 7 (39%) to 3 (17%), while moderate knowledge increased from 8 (44%) to 12 (67%). Conclusion: Feedback, discussion of findings, training, visual reminders, and distribution of alcohol-based hand rub, as part of a criterion-based audit is a powerful way of improving hand hygiene performance and knowledge in surgical wards.