Color Doppler ultrasound is the diagnostic cornerstone of vascular assessment. Almost all arteries and veins of the human body are accessible to this diagnostic imaging, which as a result is very often used as first-line diagnostic test. Recent technological developments in high-end ultrasound machines enable us to optimize image quality in color-coded duplex ultrasound of arteries and veins. To obtain an optimal instrument setting, all relevant adjustments of imaging must be considered. In B-Mode ultrasound, the basic vascular imaging method, the most important settings to optimize are ultrasound frequency, gain, dynamic range, and focus, whereas color Doppler depends on angle supersonic sounding and its application in clinical practice. Most mistakes in measuring blood flow velocities, a frequent cause of misinterpretation, result from insufficient angle correction. Cardiac pathologies may result in typical changes of arterial and venous Doppler curves.