The purpose of the study was to describe the sense of coherence (SOC) of three groups of Finnish polytechnic students (n=287) at the beginning of their studies and to follow it during a period of 3 year amongst the health care students (n=63) of this group. The associations between SOC and smoking, drinking and physical exercise were also studied. The data were collected with a questionnaire which included Antonovsky's (Adv. Nurs. Sci. 1(1983)37) SOC scale. Data analysis was with SPSS statistical software. The students showed a strong sense of coherence at the beginning of their studies. Physical activity was related to the strength of SOC, but no association was found with smoking and drinking. Health care students showed a stronger SOC at the beginning of their studies than the two other groups. During the follow-up focused on the health care students, SOC weakened in 6%, remained unchanged in 65% and strengthened in 32% of the participants. Smoking, drinking and physical exercise showed no association with these changes. Future research should be focused on identifying factors that are related to SOC during education.