BACKGROUND: Postpartum blues in Indonesia has a high prevalence at 37% to 67%. Postpartum blues syndrome has been described as varying changes in the affective domain, such as feelings, behavior, or thoughts, that can be influenced by the roles and tasks of women, along with their social, cultural, and economic support. Instruments that measure maternal blues through bonding attachment behavior have never before been developed in Indonesia. OBJECTIVE: This study aimed to develop a maternal blues scale through bonding attachments to predict postpartum blues. METHOD: The research design consisted of three stages: 1) phenomenology design and focus group discussion; 2) development and construction of the maternal blues scale, and 3) a cross-sectional study to measure validation of the scales. Respondents were postpartum mothers in the first week after birth. The sample comprised 501 participants. Sampling was done by consecutive sampling at the Public Health Center (PUSKESMAS) in the South Jakarta area. Data analysis used exploratory factor analysis (EFA) and confirmatory factor analysis (CFA), correlation, and a diagnostic testing . RESULTS: Item analysis produced 32 items consisting of 24 items regarding the mother's role and duties as internal factors and eight factors involving social, cultural, and economic support as external factors. Both factors were valid and reliable in predicting postpartum blues with indicators (t loading factors ≥ 1.96, standardized loading factor (SLF) ≥.50, internal factors: construct reliability (CR) ≥ .70 and extraction variants (VE) ≥ .50 and external factors: CR ≥ .74 to .83 VE ≥ .50 to .63). The relationship with Kennerley's maternity blues as a gold standard was significant. Internal factors had a score of 53, with a sensitivity of 60.2%. The external factors score was 19, with a sensitivity of 77.3%. CONCLUSION: The new scale for postpartum blues prediction developed displayed internal consistency and validity of each indicator (internal and external factors) that was good (CR ≥ .70; VE ≥ .50). This scale provides a feasible tool to predict postpartum blues.