OBJECTIVES: Fear for hypoglycemia has an impact on type 2 diabetes mellitus (T2DM) patients’ Health-Related Quality of Life (HRQoL). The Worry Subscale of the Hypoglycaemic Fear Survey-II (HFS-II) is a widely used tool. The objective is to test the internal consistency, validity and reliability of a Spanish version of HFS-II for determining the impact of fear for hypoglycemia on T2DM patients’ HRQL in Spain. METHODS: Observational, cross-sectional, multicentre design. T2DM patients diagnosed from at least 1 year were recruited consecutively. Use of research tools:1)Audit of Diabetes-Dependent Quality of Life/ADDQoL questionnaire [-9 to +9, more negative scores indicate greater negative impact of diabetes on QoL];2)Worry subscale of HFS-II [0-72, higher scores indicate increased fear];3)Visual Analogue Scales (VAS) [0-10, higher scores indicate greater fear and impact of hypoglycemia]. For determining HSF-II internal consistency, validity and reliability, next parameters were calculated: Cronbach's alpha; ceiling/floor effects; correlations between similar items scores of HFS-II/ADDQoL and between scores of two anchor questions (VAS) /HFS-II. RESULTS: A total of 3,812 patients (661 health care centers) participated in the study [men (53.57%);mean(SD) age 63.70(11.37) years;mean(SD) time from T2DM diagnosis 9.67(6.91) years]. 44.88% of patients referred at least one episode of hypoglycemia in the previous six months. Mean(SD) HFS-II subscale score was 24.41(17.05). It was higher in patients with hypoglycemia [31.32(15.71)] compared to those without [18.85(16.03)](p<0.0001). Cronbach's alpha was 0.964. A negative correlation was found between ADDQoL and HFS-II mean scores (-0.441;p<0.0001). Items that explore physical capacity, family, confidence, motivation, future and dependence in ADDQoL and in HFS-II showed the highest correlations. Anchorage questions’ (VAS) correlations (0.522-0.597) demonstrated an acceptable face validity of the HFS-II individual items. Ceiling/floor effects below 20% suggest its good functionality.  CONCLUSIONS: These preliminary results show that the HFS-II is consistent, valid and reliable for assessing fear for hypoglycemia in T2DM patients in Spain.