Glucagon-like peptide 1 (GLP-1) stimulates insulin secretion in a glucose-dependent manner, but its short half-life limits its therapeutic potential. We tested NN2211, a long-acting GLP-1 derivative, in 10 subjects with type 2 diabetes (means ± SD: age 63 ± 8 years, BMI 30.1 ± 4.2 kg/m², HbA_1c 6.5 ± 0.8%) in a randomized, double-blind, placebo-controlled, crossover study. A single injection (7.5 μg/kg) of NN2211 or placebo was administered 9 h before the study. β-cell sensitivity was assessed by a graded glucose infusion protocol, with glucose levels matched over the 5–12 mmol/l range. Insulin secretion rates (ISRs) were estimated by deconvolution of C-peptide levels. Findings were compared with those in 10 nondiabetic volunteers during the same glucose infusion protocol. In type 2 diabetic subjects, NN2211, in comparison with placebo, increased insulin and C-peptide levels, the ISR area under the curve (AUC) (1,130 ± 150 vs. 668 ± 106 pmol/kg; P < 0.001), and the slope of ISR versus plasma glucose (1.26 ± 0.36 vs. 0.54 ± 0.18 pmol · l[min⁻¹ · mmol⁻¹ · kg⁻¹]; P < 0.014), with values similar to those of nondiabetic control subjects (ISR AUC 1,206 ± 99; slope of ISR versus plasma glucose, 1.44 ± 0.18). The long-acting GLP-1 derivative, NN2211, restored β-cell responsiveness to physiological hyperglycemia in type 2 diabetic subjects.