Background/Aim. Patients with acute coronary syndrome (ACS) and diabetes mellitus (DM) have an increased risk of major adverse cardiovascular events (MACE) after percutaneous coronary intervention (PCI), which is not estimated sufficiently-multidimensionally in terms of type and severity of the ACS and/or DM and angiographic findings. The study was intended to validate and develop an index of metabolic, angiographic, anatomic and clinical risk factors for one-year MACE after conducted PCI in patients with ACS and DM. Methods. A prospective cross-section study was performed in patients with DM and ACS. In the PCI period the following risk factors where were recorded: 1) age and metabolic variablesglycosylated hemoglobin (HbA1c), total cholesterol, triglyceridemia; 2) endocrinological variables-DM therapy, tip of DM; 3) ACS modality; 4) radiological / anatomical variable-SYNTAX score and 5) clinical variables in modified ACEF score. One-year MACE were recorded. Results. From a total of 136 consecutive patients, 55 of them developed at least one MACE in one-year followup. A high predictive risk index was evaluated that assessed particularly or associated risks for one-year MACE (c statistic = 0.879) in the study population, defined by: SYNTAX score > 21, modified ACEF score > 1.38, HbA1c ≥ 8 (%), triglyceridemia ≥ 2.3 (mmol/L) in patients with insulin therapy, and ACS modalityunstable angina pectoris. The constructed Risk Index for one-year MACE (MACERI) has better predictive characteristics than SYNTAX score (c statistic = 0.798), as well as ACF score (c statistic = 0.744). Conclusions. MACERI can potentially have great application in future risk factors studies for one-year MACE in patients with DM and ACS who underwent PCI, because with it the effects of these factors measure multidimensionally at valid and accurate manner.