Observation is one of the basic methods in science. It is not only an epistemological method itself, but also an important competence for other methods like experimenting or comparing. However, there is little knowledge about the relation with affective factors of this inquiry method. In our study, we would like to find out about the relations of emotional well-being and involvement with children's observation competency. Seventy preschool children participated in our test observing a living mouse, a snail and a fish. From their behaviour in the test situation, we coded their observation competency as well as their emotional well-being and involvement. The data show that both emotional well-being and involvement are significant predictors of children's observation competency. Further analyses confirm our hypothesis of a mediating role of involvement between well-being and the performance in the observation task. In conclusion, theoretical and practical implications of these results are discussed.