Lactic acidosis (LA) due to metformin prescription is a rare condition; however, this circumstance is accompanied by a very high rate of death (≥50%). Accumulation of metformin alone is hardly a cause of LA, and more than 90% of patients with metformin-associated LA had a hypoxic condition that could prompt hazards of LA. LA related to this drug occurs after iodinated contrast material (ICM) exposure when other contraindications to metformin use, particularly renal insufficiency neglected and leading to high plasma metformin accumulation. One of the most common questions for radiologists is when and at what level of kidney function this agent should be discontinued in cases receiving ICM and restarted again. In this study, we assess the requirement of metformin discontinuation in diabetic patients with chronic kidney disease (CKD) who are candidates for ICM. Therefore, we evaluate the step and withholding time of metformin discontinuation in CKD patients programmed for angiography with an intravenous contrast agent. Results demonstrated that for patients with uncertain renal function and individuals with normal estimated glomerular filtration rate and other diseases, the assessment to discontinue metformin (Before or at the time of the procedure) and when to reinitiate this drug should be made the decision, based on the individual’s circumstances.