The World Health Organization (WHO) developed the Safe Childbirth Checklist (SCC) to increase the application of essential birth practices to ultimately reduce perinatal and maternal deaths. We study the effects of the SCC on health workers safety culture, in the framework of a cluster-randomized controlled trial (16 treatment facilities/16 control facilities). We introduced the SCC in combination with a medium intensity coaching in health facilities which already offered at minimum basic emergency obstetric and newborn care (BEMonC). We assess the effects of using the SCC on 14 outcome variables measuring self-perceived information access, information transmission, frequency of errors, workload and access to resources at the facility level. We apply Ordinary Least Square regressions to identify an Intention to Treat Effect (ITT) and Instrumental Variable regressions to determine a Complier Average Causal Effect (CACE). The results suggest that the treatment significantly improved self-assessed attitudes regarding the probability of calling attention to problems with patient care (ITT 0.6945 standard deviations) and the frequency of errors in times of excessive workload (ITT -0.6318 standard deviations). Moreover, self-assessed resource access increased (ITT 0.6150 standard deviations). The other eleven outcomes were unaffected. The findings suggest that checklists can contribute to an improvement in some dimensions of safety culture among health workers. However, the complier analysis also highlights that achieving adherence remains a key challenge to make checklists effective.