Lung lymph flow was normalized for lung weight and total lung lymph flows were calculated in five mongrel dogs using a kinetic analysis of albumin distribution between the pulmonary capillaries, interstitial fluid, and pulmonary lymph. Using prenodal tracheobronchial lymph an intravenous bolus of 125I-labeled albumin equilibrated between plasma and lymph with mean T1/2 of 2 hr 22 min. The mean volume of interstitial fluid drained by the cannulated lymphatics was 9.9 ml which corresponded to the extravascular albumin distribution volume of 31% of the total lung weight. Lung tissue hematocrit was determined using 51Cr-labeled red cells and 125I-albumin and averaged 92% of the simultaneous mixed venous hematocrit. The extravascular albumin and 99mTc-DTPA (diethylenetriamine pentacetic acid) spaces in lung were corrected for differences between tissue and mixed venous hematocrit and were 18.5 and 33.0 ml/100 g, respectively. This indicated that albumin distributed in 57% of the interstitial volume at 4 hr after injection. Lung lymph flow normalized to postmortem lung mass during baseline conditions was 0.060 ml/min/100 g after correction for tissue hematocrit differences. Normalized lymph flows are used for quantitative comparisons of lung lymph protein flux data between different types of experiments.