Hyperhomocysteinemia is a well-established risk factor for cardiovascular diseases. The aims of this study were to longitudinally investigate, in a group of elite athletes, plasma homocysteine levels and to search for relationships with the muscular workload and the vitamin status. One hundred and three athletes (59 males and 44 females, respectively) were evaluated in different periods: namely the recovery period, the training period, and the competition period; 84 subjects (37 males and 47 females), served as controls. The evaluation sessions consisted in blood sampling and medical examination. The percentages of athletes with normal and elevated homocysteine levels, defined by levels below or above the limit of 15 mumol/l, were 68.0% and 32.0%, respectively, in the recovery period, and these percentages remained unchanged during the following periods. In the control group, relevant percentages were 92.9% and 7.1%, respectively. The comparison between plasma homocysteine of male and female, evaluated in the recovery period, showed significantly higher levels in the former group (18.8+/-18.0 micromol/l vs 10.7+/-5.9 micromol/l, p<0.001 respectively), as well as a higher proportion of individuals with hyperhomocysteinemia (24/59 vs 9/44, p<0.05). The correlation analyses showed a weak but significant negative correlation between homocysteine and folate in the three periods considered, while no significant relationship was observed between homocysteine and creatine-kinase. We found excess prevalence of hyperhomocysteinemia in elite athletes of winter sports. A strategy to understand which mechanisms in these athletes subserve hyperhomocysteinemia is essential in order to reduce the potential risk for future cardio-vascular morbidity and mortality.