This is a pilot, interventional clinical trial to assess the effectiveness and safety of artificial pancreas (AP) using the ARG algorithm closed-loop system in a monitored 3-day period outpatient study. Once the safety of the device has been validated in the open-loop first 3-day period (continuous subcutaneous insulin infusion (CSII) plus continuous glucose monitoring (CGM)) the investigators will move the study to the second 3-day closed-loop period, without carbohydrate (CHO) counting.

Inclusion Criteria:

• Patient has been diagnosed with T1DM at least two years ago and has been using an insulin pump and a CGM for at least 6 months prior to the trial first visit
• Patient is >18 and <65 years
• Patient has HbA1c < 10%
• Woman in premenopausal age agrees to use contraceptive methods
• Woman in premenopausal age has negative B-HCG in the tests performed in the trial
• Patient is trained in CHO counting
• Patient has signed informed consent and has the ability to understand the nature and intent of the study including the ability to comply with study procedures and is willing to keep scheduled visits

Exclusion Criteria:

• Patient has been hospitalized for diabetic ketoacidosis in the last 12 months
• Patient has experienced severe hypoglycemia with loss of consciousness in the last 12 months
• Patient has a history of coronary disease or cardiac failure
• Patient with uncontrolled arterial hypertension
• Patient with a condition that makes the researcher believe that it might increase the chance of hypoglycemia
• Patient has symptoms compatible with active infectious disease
• Patient has Cystic Fibrosis
• Pregnant women, or women with the intention of getting pregnant; women breastfeeding
• Patient has been hospitalized for psychiatric treatment in the last 6 months.
• Patient with a diagnosis of adrenal disease
• Patient has abnormal laboratory values for liver function: transaminase > 2x upper limit normal
• Patient has abnormal laboratory values for renal function: GFR < 60 ml/min/1.73m2
• Patient has active gastroparesis
• Patient is under oncological treatment
• Patient has taken acetaminophen 72 hours previous to the study