Curriculum for Agricultural Science Education (CASE) was first offered in 2007 with two foundational courses built on inquiry-based learning. Ten courses are now offered, each requiring intensive training and teacher development for effective use. Guided by National Science Education standards and a constructivist learning theory framework, the study used online survey research methods to explore teachers' perceptions of and practices associated with inquiry-based teaching and learning when using CASE curriculum. A survey link was distributed in September 2018 to teachers certified in an introductory CASE course (Agriculture, Food, and Natural Resources) and a higher-level, more inquiry-based CASE course (Food Science and Safety) for comparison. The online questionnaire was completed by 392 participants for a usable response rate of 32%. Major findings in the study included (1) participants in both groups have an understanding of open inquiry but struggled in identifying structured and guided inquiry; (2) participants over-estimated the amount of open inquiry in the curriculum; and (3) participants showed mixed interpretations of inquiry-based and problem-based instruction among both groups. Participant ratings of the CASE curriculum were generally favorable, although results showed that teachers frequently remove or skip lessons and teach courses in a semester or quarter format, contrary to CASE recommendations. Findings are discussed in the context of improved training and other recommendations to help teachers use the curriculum in its intended manner and to get the most benefit from its use.