The purpose of this study was to examine the research trends and implications of optimism, aconcept of positive psychology that provides a new paradigm for understanding humans. Inparticular, this study on optimism focused on the significance of optimism during childhood. We have examined the various trends and approaches in the study of optimism in Korea, having consulted a total of ninety-five dissertation papers, and also analyzed the distribution, research methods, measurement tools, and research contents of the seprevious studies. In summary, the following results were derived from the analysis: First, the number of studies with adult subjects was highest, followed by studies with school-aged children (elementary, middle school and high school); however, there was a lack of studies on pre-school children. In terms of research methods, most cases involved quantitative studies, and the preferred measurement tool was Scheier, Carver & Bridges` (1994) life orientation test (LOT, LOT-R, E-LOT, YLOT). Second, our analysis of the results of Korean studies on optimism of pre-school and school-aged children found that the number of studies on the effects of the independent variables or mediator and moderator variables of optimism was highest. Studies on optimism as independent variables or mediator and moderator variables were classified into learning variables, emotional (psychological) variables and adaptive behavior variables. Studies on optimism as dependent variables were classified into personal variables, social support variables and physical environment variables. Studies concerning the utilization of optimism were classified into studies on the ways of utilizing optimism in child counseling and education and studies on the effectiveness of optimism programs. Based on such results, this study discusses the significance of the childhood stage in studies on optimism in Korea and the direction that should be taken for further development.