National science reform documents recommend several nature of science (NOS) elements to introduce to children early in the science curriculum. A researcher developed questionnaire was used to gather information from a random, national sample about early elementary teachers' perceptions of the developmental appropriateness of 12 NOS aspects for the grade level taught, ratings of the importance of the NOS elements in the K-4 curriculum, and the teachers' self-reported introduction of the NOS elements during the school year. Binary logistic regression was used to determine if the teachers' introduction of the NOS aspects could be predicted from their perceptions of developmental appropriateness and importance. At least 90% of teachers identified the inferential, empirical, and creative aspects as developmentally appropriate; over half identified another six NOS aspects as "important" or "very important." At least half of the 377 respondents reported classroom introduction of the inferential, empirical, creative, collaborative, tentative, and cultural NOS elements, as well as the idea that no single step-by-step scientific method exists. Developmental appropriateness was a significant predictor of teachers' self-reported introduction for nine of the 12 NOS, and importance was a significant predictor for all 12 NOS elements. The implications of this study for science education are discussed.