The number of patients with chronic kidney disease-CKD is still growing. Overweight and obesity present also an important problem of world public health. However, there are not many data showing possible association between obesity and incresing risk of development of renal failure recently it has been demonstrated that in obese patients secondary focal segmental glomerulosclerosis and glomerular hypertrophy appear more frequently. The aim of this study was to estimate glomerular filtration rate-GFR in patients with normal serum creatinine concentration undergoing primary angioplasty according to body mass index. The study included 1413 patients udergoing primary angioplasty for acute myocardial infarction. The following parameters were assessed: age, gender, family history of cardiovascular disease, risk factors of cardiovascular disease (hypertension, diabetes mellitus, obesity etc.), previous myocardial infarction, pre-existing heart failure, treatment given, localization of infarct, coronary stenting, serum creatinine before angioplasty, cholesterol, LDL, HDL, triglycerides, glucose, blood pressure. Of a total of 1413 patients, 1337 (94.62%, 943 M, 394 F) had correct serum creatinine concentration (below 1.5 mg/dl for men, below 1.2 mg/dl for women). Glomerular filtration rate was calculated from serum creatinine levels by using the simplified Modification of Diet in Renal Disease Study formula--MDRD, Cockcroft-Gault equation and Jeliffe formula. An average value of GFR in study group was 79.94 +/- 24.51 ml/min (Cockcroft-Gault equation), 73.02 +/- 21.96 ml/min (Cockcroft-Gault adjusted to weight), 90.37 +/- 25.1 ml/min (MDRD equation) and 77.67 +/- 21.65 ml/min (Jeliffe formula). A significant lower serum creatinine levels and GFR (assessed by 3 formulas and Cockcroft-Gault using adjusted weight) were observed in women group. In the whole study group (with normal serum creatinine levels) substantial correlation was found between age and serum creatinine concentration (r = 0.13, p > 0.001), GFR (MDRD, r = -0.37, p < 0.001, Cockcroft-Gault, r = -0.62, p < 0.001, adjusted to weight r = -0.64, p < 0.001, Jeliffe r = -0.61, p < 0.001) and also between BMI and GFR (MDRD r = 0.28, p < 0.001, Cockcroft-Gault, r = 0.31, p < 0.001, adjusted to weight r = 0.08, p < 0.001, Jeliffe r = 0.341, p < 0.001), but not with serum creatinine concentration (r = 0.03, p = 0.3). In patients with normal serum creatinine levels percentage of patients with GFR below 60 ml/min ranges from 4.79% up to 30.74%. In patients with higher BMI, higher GFR may be partially caused by glomerular hyperfiltration. Overweight or obesity are significant, but potentially changeable risk factors for development of chronic renal failure. However, chronic kidney disease is one of the complications of obesity.