Pesticide runoff from crop fields is the important concern in environment because it may affect aquatic ecosystem and human. And it is essential to find out the amount of runoff and evaluate the possible effect on aquatic organisms for the human and environmental risk assessment. However, no definite guidelines have been established and related researches are not active in Korea since too many factors were involved in pesticide runoff and it was hard to predict it by using simple data. Therefore, various runoff studies with natural field, simulated rain/field, and computer models were reviewed for the general aspect of experiments and results.