['To assess the feasibility and effectiveness of an active real-life primary care lifestyle intervention in preventing type 2 diabetes within a high-risk Mediterranean population.', 'A prospective cohort study was performed in the setting of Spanish primary care. White-European individuals without diabetes aged 45-75 years (n = 2,054) were screened using the Finnish Diabetes Risk Score (FINDRISC) and a subsequent 2 h OGTT. Where feasible, high-risk individuals who were identified were allocated sequentially to standard care, a group-based or an individual level intervention (intensive reinforced DE-PLAN [Diabetes in Europe-Prevention using Lifestyle, Physical Activity and Nutritional] intervention). The primary outcome was the development of diabetes according to WHO criteria. Analyses after 4-year follow-up were performed based on the intention-to-treat principle with comparison of standard care and the combined intervention groups.', 'The standard care (n = 219) and intensive intervention (n = 333) groups were comparable in age (62.0/62.2 years), sex (64.4/68.2% women), BMI (31.3/31.2 kg/m(2)), FINDRISC score (16.2/15.8 points), fasting (5.3/5.2 mmol/l), 2 h plasma glucose (7.1/6.9 mmol/l) and self-reported interest to make lifestyle changes at baseline. Diabetes was diagnosed in 124 individuals: 63 (28.8%) in the standard care group and 61 (18.3%) in the intensive intervention group. During a 4.2-year median follow-up, the incidences of diabetes were 7.2 and 4.6 cases per 100 person-years, respectively (36.5% relative risk reduction, p < 0.005). The number of participants needed to be treated by intensive intervention for 4 years to reduce one case of diabetes was 9.5.'] Is delaying progression to type 2 diabetes among high-risk Spanish individuals feasible in real-life primary healthcare settings using intensive lifestyle intervention?