This research aims to improve cognitive development using the ABCD-ABCD pattern method in group B children of the Tunas Jaya Randudongkal KB. This research is Classroom Action Research which was carried out in 2 cycles, each cycle consisting of two meetings. The subjects in this research were 15 children from group B of the Tunas Jaya Randudongkal KB, consisting of 10 boys and 5 girls. The data collection methods in this research are observation, interviews and documentation. The problem solving steps in this research consist of four activity stages, namely planning, implementation, observation and reflection. The data analysis used in this research is qualitative descriptive analysis. The results of the analysis in this study show a significant increase in children's cognitive development. In the initial research study, of 15 children, there were 7 children (47%) who were starting to develop (MB), 5 children (33%) who were developing as expected (BSH) and 3 children (20%) who were developing very well (BSB). In Cycle I, out of 15 children, there were 5 children (33%) who were starting to develop (MB), 7 children (47%) who were developing according to expectations (BSH) and 3 children (20%) who were developing very well (BSB). In Cycle II, out of 15 children, there were 2 children (13%) who were starting to develop (MB), 7 children (47%) who were developing according to expectations (BSH) and 6 children (40%) who were developing very well (BSB). In other words, there was an increase in cognitive development in the initial study by 53%, cycle I by 67% and cycle II by 87%.