Mothers and their newborns are vulnerable to illnesses and deaths during the postnatal period. More than half a million women each year die of causes related to pregnancy and childbirth. The majority of deaths occur in less developed countries. Utilization of postnatal care (PNC) service in Ethiopia is low due to various factors. These problems problem significantly hold back the goal of decreasing maternal and child mortality. To assess mothers’ knowledge, perception and utilization of PNC in the Gondar Zuria District, Ethiopia. Our study is a community-based, cross-sectional study supported by a qualitative study conducted among 15–49 years mothers who gave birth during the last year. A multistage sampling technique was used to selected participants; structured questionnaires and focus group discussions were used to collect data. Data were entered into EPI info version 3.5.1 and exported into SPSS version 16.0 for the quantitative study and thematic framework analysis was applied to the qualitative portion. The majority of the women (84.39 %) were aware and considered PNC necessary (74.27 %); however, only 66.83 % of women obtained PNC. The most frequent reasons for not obtaining PNC were lack of time (30.47 %), long distance to a provider (19.25 %), lack of guardians for children care (16.07 %), and lack of service (8.60 %). Based on the multivariate analysis, place of residence (AOR 2.68; 95 % CI 1.45–4.98), distance from a health institution (AOR 2.21; 95 % CI 1.39–3.51), antenatal care visit (AOR 2.60; 95 % CI 1.40–5.06), and having decision-making authority for utilization (AOR 1.86; 95 % CI 1.30–2.65) were factors found to be significantly associated with PNC utilization. Mothers in the study area had a high level of awareness and perception about the necessity of PNC. Urban women and those who displayed higher levels of autonomy were more likely to use postnatal health services.