The relations between life changes, locus of control and changes in the parameters of the metabolic syndrome were examined. A three-year follow-up study of 671 randomly selected, healthy adolescents and young adults was used. Somatic parameters measured both at the baseline and the follow-up were serum insulin, serum HDL chol, serum triglyceride, SBP and BMI. Locus of control was measured with the Nowicki-Strickland locus of control scale and subjects were asked about life changes that they had faced during the follow-up period. Results showed that, in women, there were significant main effects for life changes in predicting (high) somatic risk level, whereas, in men, an opposite association was found. In addition, locus of control had a moderating effect on the life change-metabolic parameters relation, i.e. most of the life changes predicted a lower level of somatic risk in subjects with an external rather than internal locus of control. Results question the universal applicability of beneficial health effects of internal locus of control. It was suggested that accumulation of life changes might contribute, in interaction with locus of control, to the early development of the metabolic syndrome.