To study the perceived sources of stressful events in dental students and the relationship between their self-perceived stress levels and salivary IgA. Undergraduates as well as postgraduates at the Faculty of Dentistry, National University of Singapore were surveyed one month after the new term. A 38-item dental environmental stress (DES) questionnaire, with subscales of academic work (AW), clinical factors (CF), faculty and administration factors (FA) and personal factors (PF), was used to identify the potential stressors in the dental environment. A 4-point perceived stress scale was used to rank their self-perceived stress levels. Enzyme linked immunosorbent assay method was used to determine the salivary IgA level. One hundred and thirty students (81.3%--valid response rate) participated in the study. Overall, students ranked AW with the highest score (mean 2.76), followed by CF (2.67), FA (2.24) and PF (2.16). Among the 38 items of DES questionnaire, 1st year students perceived "fear of being unable to catch up if behind" as the most stressful event (mean 3.30). For 2nd and 3rd year students, examination and grades had the highest scores (mean 3.28, 3.19, respectively). Completing graduation requirements was the most important stressor for 4th year students (mean 3.89). Post graduates perceived atmosphere created by clinical faculty was most stressful to them (mean 3.05). The mean total perceived stress scores were highest (22.1) in 1st year students and lowest (21.0) in postgraduates, however, no significant different among various classes. First year students had had the lowest IgA secretion rates (geometric mean [GM] 46.8 microg/min), significantly lower (p<0.05) than postgraduates (GM 79.4 microg/min). An inverse correlation was noted between perceived stress scale and log IgA secretion rates (r= -0.20, p= 0.002). AW was also significantly inversely correlated with salivary IgA (r= -0.18, p= 0.04). Dental students in different academic years perceived different important stressors. Salivary IgA secretion rate correlated inversely with self perceived stress.