Postnatal care (PNC) in the first six weeks after birth is crucial for early diagnosis and treatment of complications to mothers and their new-born babies. However, about 40% of women in low and middle income countries do not use PNC services so that 2/3 of maternal deaths occur during postnatal period. This study aimed at assessing factors that affect the use of PNC services among women in rural Malawi. We used both quantitative and qualitative methods. A cross-sectional survey was undertaken in two rural villages in Malawi in June 2017. A structured questionnaire was administered to 73 women who had completed a pregnancy between 0-12 months before the interview. Two focus group discussions with women and two in-depth interviews with midwives were also conducted. Descriptive statistics and chi-square tests were used for analysis of quantitative data. Content analysis was used to analyze qualitative data. Out of the 73 participants, 69.9%(n= 51) reported to have used PNC services within six weeks after they had completed a pregnancy. Mode of transportation (p-value= 0.022) and presence of complications (p-value= 0.03) were found to be significantly associated with PNC service utilization. Qualitatively, the most cited reasons for not using PNC services were lack of knowledge of the existence of PNC services, lack of transport money, and cultural beliefs. Over half of the women who were involved had used PNC services although many more had no knowledge thereof. To increase utilization and knowledge of PNC services, community awareness needs to be intensified.