Objective: to analyze the effects of manual chest compression using neo automatic code on the accuracy of compression depths. Methods: This study used a quantitative, post test quasi-experimental design with a control group. The samples were 74 cardiac arrest patients in two hospitals in Surakarta and Klaten, who were selected using purposive sampling technique. The data were analyzed by the Mann-Whitney test. Results: the mean of accuracy of compression depth in the control group was 68.10 ± 17.60%, and in the treatment group was 83 ± 6.04%. The result of statistical analysis showed that there were differences in the accuracy of compression depth in the intervention and control group with p-value of 0.000. Conclusion: there were effects of manual chest compression using neo automatic code on the accuracy of compression depths. Neo automatic code could improve the accuracy of chest compression depths.