To study the prevalence, risk factors, and vascular disease associated with moderate and severe hypertriglyceridemia in an active working population.Cross-sectional study of 594,701 workers from all Spanish geographical areas, occupation sectors, ages, and sexes who underwent a yearly routine checkup. Data collected from participants included age, sex, anthropometric measurements, vascular risk factors, lipidic profile and basic biochemical analysis, from a fasting blood sample. A cardiovascular risk assessment was performed.The study population included 428,334 males and 166,367 females, mean age 36±10 years. A total of 95,673 (16%) workers had mild hypertriglyceridemia (HTg) (Tg 150–399mg/dL), 7,081 (1.1%) had moderate HTg (400–999mg/dL), and 224 (0.03%) had severe HTg (≥1000mg/dL). Of workers with hypertriglyceridemia, 90% were male. Age, obesity, type 1 and 2 diabetes, alcohol consumption, and vascular disease were associated with hypertriglyceridemia. Cardiovascular risk gradually increased for each HTg category. Amongst risk factors, the major independent predictor of mild-HTg was obesity (OR 2.42, CI 95% 2.37–2.48), whereas diabetes was a predictor of moderate HTg (OR 3.64, CI 95% 3.17–4.18) and severe HTg (OR 7.35, CI 95% 4.27–12.66). In multivariate analyses, HTg was gradually associated with vascular disease, even after adjusting for other risk factors.In this working population, preventive programs for HTg and associated vascular disease should consider obesity–diabetes control as its first objective.