Objective Two non-radioactive methods for determining glomerular filtration rate ( GFR) in conscious rat using FITC-labeled inulin ( FITC-inulin) and micro-osmotic pumps were evaluated． Methods FITC-inulin ( 24% ) was dissolved in 0． 9% NaCl and the concentration decreased to 8% after 24 h of dialysis． Two micro-osmotic pumps filled with 200 μL of 8% FITC-inulin were inserted into the peritoneal cavity of rats． After their complete recovery from anesthesia，the rats were housed individually in metabolic cages． Urine and the residual fluorescence remaining on the cages were collection over 24 h on day 7 after micro-osmotic pump implantation． Blood sample was collected through the saphenous vein at the end of 24-h urine collection． Only blood was sampled using the same method in another group． GFR was evaluated on day 7 after micro-osmotic pump implantation using two methods expressed in microliters per minute，microliters per minute per kilogram body weight and per gram kidney weight． Results Based on the approach measuring urinary inulin clearance with urine collection and without urine collection the estimated GFR was ( 2. 31 ± 0. 33) microliters per minute and ( 2. 53 ± 0. 33) microliters per minute ( P = 0. 564) ，respectively． These values of GFR in conscious rats were only ca． 70% of that obtained in anesthetized rats determined in other previous studies． It was revealed that anesthesia may significantly influence GFR． Conclusions The results of the present study demonstrate the feasibility of the osmotic micropump approach to monitor GFR in conscious rat using FITC-inulin． Especially，the method without collecting urine is more convenient．