OBJECTIVES: Subclinical hypothyroidism (SH) is typically defined as asymptomatic, characterized by slightly increased serum thyrotropin (TSH) levels and normal serum free thyroxine concentrations. SH is common among general population, especially in middle-aged women most often after menopause, and it is related to cardiovascular events. The objective of this analysis was to estimate burden of disease of SH and it’s evolution to clinical hypothyroidism (CH) in Spain. METHODS: The recommended methodology by WHO for burden of disease studies was used in this analysis. Disability-adjusted life years (DALY), years of life lost (YLL), years life with disability (YLD) and mortality related to SH and CH were calculated based on the adjusted attributable fraction. Prevalence of risk factors in general population as well as HR, were obtained from literature review and official sources (CMBD, hospital mortality register). RESULTS: In Spain, the number of patients with SH and CH was estimated at 2,767,124. Among them, TSH concentrations ranged between 4.5-6.9 mUI/L in 1,949,820 patients; between 6.9-10 mUI/L in 539,988 patients and between 10-19.9 mUI/L in 278,317 patients. Every year, 12,608 cardiovascular events, 1,388 cardiac deaths and 30,550 DALY (13,124 YLL and 17,426 YLD) would be attributable to SH. SH represented between 1.6-7.3% of cardiovascular DALY. CONCLUSIONS: Both the extensive socioeconomic burden of SH and the risk of developing clinical hypothyroidism and subsequent cardiovascular health risks among patients with SH is to be considered. This suggests the utility of SH screening for patients with risk factors, after assessing the efficiency of screening techniques.