OBJECTIVES: This registry evaluated the effectiveness of an insulin glargine-based regimen in patients with type 2 diabetes (T2D) in clinical practice settings in Spain. METHODS: Patients who switched from neutral protamine Hagedorn (NPH) insulin to glargine at four to nine months prior to inclusion (Study Group) and patients maintained on NPH ≥12 months (Control Group) were included (ratio 2:1) in this cross-sectional, single-visit registry. Retrospective data from four to nine months prior to inclusion and current data at a study visit were recorded. The Diabetes Treatment Satisfaction Questionnaire (DTSQ) and the change version (DTSQc) were completed by patients in both groups. RESULTS: Of 1662 patients enrolled, 1482 were included in this analysis (males/females 690/759): median age 63 (range 19–92) years, BMI 28.5 (17.6–54.9) kg/m2 and diabetes duration 10.8 (0.5–49.0) years. At the switch, mean±SD HbA1c was 7.9±1.1 and 8.3±1.2% in the Control and Study Groups, respectively. At study visit, 506 (34.1%) and 976 (65.9%) patients were treated with NPH (median dose 36 [8–110] IU) and glargine (30 [6–100] U), respectively; 65.0% and 73.2% were taking oral antidiabetic drugs. Mean±SD fasting blood glucose was 157.3±47.5 and 137.8±40.7 mg/dL, (p<0.0001; Student’s t test) and HbA1c reduction was 0.2±0.8% (adjusted mean change: 0.363±0.834%) and 1.0±1.0% (0.874±0.811%) (p<0.0001, t test; p<0.0001, ANCOVA for adjusted change). 241 (47.6%) and 213 (21.8%) patients reported symptomatic hypoglycaemia in the last month and 42 and 13 patients had nocturnal hypoglycaemia in the Control and Study Groups, respectively. Improvements in DTSQc scores were reported in the Study Group compared with the Control Group (p<0.0001; t test). CONCLUSIONS: In this registry in Spain, better glycaemic control was achieved in T2D patients who were switched from NPH to glargine-based regimens compared with patients maintained on NPH. Glargine is related to less frequent symptomatic hypoglycaemia and improves treatment satisfaction.