Although class size has been researched extensively at the primary and secondary levels, studies at the college level are fewer in number and lack any substantive assessment of classroom behavior. The purpose of this study was to assess the relationship among lecture size and both student and faculty attitudes and behavior as well as student performance in an introductory college-level nutrition course. Two sections of NFSC 100, with different lecture sizes, (n = 141- large, 347- very large) were taught in Spring 1997 by the same 3-member teaching team, using the same teaching resources. The only performance differences related to lecture size occurred with the in-lecture quiz, where students in the large lecture section performed significantly better than students in the very large lecture section (p < 0.05). Student attitudes regarding classroom environment were significantly less favorable (p< 0.01) and students asked fewer questions in the very large lecture section. Lecture and lecture notes were rated by students as the most important resources in terms of their contribution to learning and these attitudes were significantly and positively correlated with performance. Actual attendance in lecture also correlated positively with performance, regardless of the lecture size (p < 0.01). Our results suggest that classroom climate may be negatively influenced by increasing the size of the large lecture class but students are independent learners and many are able to compensate when given time to prepare outside of class.