This trial is a multi-center, open-label, randomized, parallel group trial in patients with T2DM comparing the efficacy and safety of Mylan's insulin glargine with that of Lantus®. Patients with an established diagnosis of T2DM per ADA 2014 criteria and who satisfy the selection criteria will be included in the trial. This will be followed by a 24-week randomized, comparative, parallel-assignment treatment period with Mylan's insulin glargine or Lantus® (in addition to other anti-diabetic drugs). After the treatment period, there will be a follow-up visit; 4 weeks after the patient has been put back on approved medications.