The present study was designed to evaluate the short-term effects of i.v. administration of furosemide on key-functions in the kidney cortex and the outer and inner medulla of rats by magnetic resonance imaging (MRI). Renal tissue water content, renal tissue oxygenation (in relation to the MR parameter R2*), the apparent diffusion coefficient (ADC) of water and renal blood flow were examined. Furosemide administration resulted in increased water content in all regions of the kidney. In parallel, ADC was significantly reduced in the cortex (2.7±0.1 x10^-3 mm²/s to 2.3±0.1 x10^-3 mm²/s; p<0.01) and in the outer medulla (2.3±0.1 x10^-3 mm²/s to 2.0±0.1 x10^-3 mm²/s; p<0.01), indicating that the intra to extracellular volume fraction of water increased in response to furosemide administration. Furosemide also decreased the blood oxygenation levels (R2* decreased) in the cortex (49.1±2.9 to 40.9±2.0 s^-1; p<0.01), outer medulla (41.9±2.8 to 33.2±1.6 s^-1; p<0.01) and inner medulla (37.1±2.9 to 26.7±1.8 s^-1; p<0.01), indicating an increased amount of oxygenated hemoglobin in the renal tissue. Moreover, renal blood flow decreased in response to furosemide (6.9±0.2 to 4.4±0.2 ml/min; p<0.001). In conclusion, furosemide administration was associated with increased renal water content, an increase in the intra to extracellular volume fraction of water, an increased oxygen tension and a decrease in the renal blood flow. Thus, MRI provides an integrated evaluation of changes in renal function, leading to decreased renal water and solute reabsorption in response to furosemide, and in addition, MRI provides an alternative tool to monitor non-invasively changes at the cellular level.