The use of inquiry-based laboratory in college science classes is on the rise. This study investigated how five nonmajor biology students learned from an inquiry-based laboratory experience. Using interpretive data analysis, the five students' conceptual ecologies, learning beliefs, and science epistemologies were explored. Findings indicated that students with constructivist learning beliefs tended to add more meaningful conceptual understandings during inquiry labs than students with positivist learning beliefs. All students improved their understanding of experiment in biology. Implications for the teaching of biology labs are discussed. © 2003 Wiley Periodicals, Inc. J Res Sci Teach 40: 986–1024, 2003