Overall childhood vaccination coverage remains relatively low in many parts of India, and there is substantial heterogeneity within states and across population groups. This study uses a factorial cluster randomized trial to examine the impact of SMS messages (reminders or reminders+congratulations message) and health worker incentives for childhood vaccinations. We use administrative data to identify children eligible for vaccination shots and their due dates. In the SMS arm, parents receive reminder messages ahead of the due date. In a subarm, parents who took their child to get vaccinated also receive a congratulations message. In the incentive arm, ASHA health workers receive a small incentive for each shot. We measure receipt of vaccination, and impact, using the same administrative data. In addition, we conduct veracity surveys to confirm that the administrative data are complete.