The main purpose of this research was to investigate the relationship between educational climate and intrinsic motivation to study with engineering students' affective commitment in Shiraz University. Statistical population is whole of bachelor students of engineering college in Shiraz University. By stratified-random sampling method, 258 students were selected. Research instruments were Intrinsic motivation questionnaire (Chooi, 2009) and educational climate questionnaire and affective commitment subscale from organizational commitment questionnaire (Alen-Mayer, 1990). After computing their validity and reliability of instruments, they were distributed among samples. Multiple regressions were used for data analysis. The results showed: 1) Educational climate variable was stronger anticipant for the affective commitment of students. 2) Dimensions of interest, tension and value from intrinsic motivation to study were strongest anticipants for their affective commitment based on gender, field and residence. 3) Dimension of "Social Integration between Student-Faculty" from educational climate were strongest anticipant for theirs' affective commitment based on gender, field and residence.