Transthoracic Doppler echocardiography was used to evaluate the technique of measuring and normal patterns of pulmonary venous flow in fourteen normal dogs. Polyphasic pulmonary venous flow profiles were obtained in all dogs, consisting of one (S) or two (SE and SL) systolic forward flow waves, one early diastolic forward flow wave (D), one reverse flow wave (R) related to atrial contraction, and one reverse flow wave (R2) observed after cessation of systolic flow. Pulmonary venous flow was laminar in 9 dogs (65%). Maximal flow velocity during systole (0.39 ± 0.14 m/sec) was significantly lower (P < 0.01) than in early diastole (0.56 ± 0.14 m/sec). During late diastole peak flow velocity was 0.20 ± 0.08 m/sec and maximum R2 velocity was 0.17 ± 0.05 m/sec. Duration of mitral A-wave was significantly greater (P < 0.05) than R-wave duration in all dogs (0.075 ± 0.10 vs 0.058 ± 0.012 sec). These results can be used for comparison with patterns found in disease states.