BACKGROUND: Since 2018, maternal mortality in Semarang City, Indonesia, has mostly (75%) occurred during the postpartum period. Therefore, a health intervention is necessary to improve safe and effective postpartum care. During the Covid-19 pandemic, a mobile-based health intervention is preferred due to the government’s regulation of COVID-19 safety prevention. This study aimed to determine the effectiveness of the mobile-health interactive message on the postpartum care behavior of mothers and their husbands.METHODS: The study was conducted in a quasi-experimental design. It includes the treatment group and the control group, in which each group consists of 46 pairs of pregnant women in the third trimester and their husbands. The research subjects were chosen through the purposive sampling technique. Data collection was conducted via interviews and observations. The m-health intervention is carried out in the form of text messages, images, videos, and interactive mentoring. The latter was carried out through group messaging via the WhatsApp application for the treatment group. Meanwhile, the control group received regular counseling from the local Community Health Center. Data analysis was performed by Mann-Whitney test, unpaired T-Test, Chi-Square Test dan Fisher Exact Test.RESULTS: Intervention for 2.5 months increased the knowledge of mothers and husbands. The intervention for 3.5 months improved the mother’s attitude, but not the husband’s attitude. The intervention also improves maternal practices related to postpartum visits, such as Early Initiation of Breastfeeding assistance requests from health workers, iron tablets and nutritious food consumption, personal hygiene, postpartum danger signs monitoring, and the husband’s practice of accompanying mothers during postpartum visits.CONCLUSION: Mobile-Health interactive messages effectively improved postpartum care behavior for mothers and their husbands.KEYWORDS: Text messaging, Health Promotion, COVID-19, Postpartum Care