Introduction: Data on long-term patterns of weight change in relation to the development of metabolic syndrome (MetS) are scarce. The aim of the study was to evaluate the impact of weight change on the risk of MetS in men. Material and Methods: Prospective longitudinal observation (17.9 ± 8.1 years) of apparently healthy 324 men aged 18–64 years. Metabolic risk was assessed in weight gain (⩾ 2.5 kg), stable weight (> −2.5 kg and < 2.5 kg) and weight loss (⩽ −2.5 kg) groups. Adjusted relative risk (RR) of MetS was analyzed using multivariate logistic regression. Results: The prevalence of MetS over follow-up was 22.5%. There was a strong relationship between weight gain and worsening of MetS components among baseline overweight men. Long-term increase in weight was most strongly related with the risk of abdominal obesity (RR=7.26; 95% CI 2.98–18.98), regardless of baseline body mass index (BMI). Weight loss was protective against most metabolic disorders. Leisure-time physical activity (LTPA) with energy expenditure > 2000 metabolic equivalent/min/week was associated with a significantly lower risk of MetS. Conclusions: Reducing weight among overweight and maintaining stable weight among normal-weight men lower the risk of MetS. High LTPA level may additionally decrease the metabolic risk regardless of BMI.