Based on the Indonesian health profile in 2022, the number of toddlers monitored for growth and development is 78.3%, and toddlers served by Stimulation, Detection, and Early Intervention of Child Growth and Development (SDDTIK) is 61.3%, where South Sumatra province is 85.6%. This study aims to determine the relationship of parental knowledge and education to early detection of the development of toddlers aged 12-59 months through the use of MCH books in the UPT Puskesmas Buay Pemaca Work Area. This study is a quantitative study with a cross-sectional approach. The population is all mothers who have toddlers aged 12-59 months, totaling 1,402. A sample of 104 respondents was taken with a purposive sampling technique. Data were analyzed by the Chi-square test. The results showed that the frequency distribution of knowledge mostly had knowledge in the sufficient category (54.8%), higher education (59.6%), and most of them did early detection through the use of MCH books (79.8%). The results of statistical analysis showed that there was a significant relationship between knowledge and early detection of the development of toddlers aged 12-59 months through the use of MCH books (0.000), and there was a significant relationship between education and early detection of the development of toddlers aged 12-59 months through the use of MCH books (0.045). There is a relationship between parents' knowledge and education on early detection of the development of toddlers aged 12-59 months through the use of MCH books in the Working Area of UPT Puskesmas Buay Pemaca.