Purpose: The aim of this study was to compare job satisfaction, quality of life (QOL), incident report rate and overtime hours for 12-hour shifts and for 8-hour shifts in a pediatric intensive care unit (PICU). Methods: A descriptive survey was conducted with a convenience sample of 36 staff nurses from a PICU in a regional hospital in Korea. Data were collected using self-administrated questionnaires regarding job satisfaction and QOL at 6 months before and after the beginning of 12-hour shifts. Incident report rate and overtime hours for both 12-hour and 8-hour shifts were compared. Comparisons were made using $x^2$-test, paired t-test and Mann-Whitney U test. Results: After 12-hour shifts were initiated, job satisfaction significantly increased (t=3.93, p<.001) and QOL was higher for nurses on 12-hour shifts compared to 8-hour (t=7.83, p<.001). There was no statistically significant change in incident report rate ($x^2=0.15$, p=.720). The overtimes decreased from $36.3{pm}34.7$ to $17.3{pm}34.9$ minutes (Z=-8.91, p<.001). Conclusion: These results provide evidence that 12-hour shifts can be an effective ways of scheduling for staff nurses to increase job satisfaction and quality of life without increasing patient safety incidents or prolonged overtime work hours.