With the continuous increase of network capacities, video transmissions in medicine are becoming an effective tool for second opinion diagnosis, archiving and teaching environments. This study investigates video compression delay times and transmission impairments for different compression formats and describes the resulting picture qualities. For the evaluation endoscopic video sequences were produced with different compression formats and bandwidth requirements. In a second step an impairment tool was used to introduce error rates to the video material to simulate network behavior. A group of medical experts evaluated the video sequences rating visibility of errors, artifacts, sharpness, overall picture quality and suitability for a medical diagnosis. The results clearly establish lower boundaries for picture quality deteriorated by compression and network impairments, and introduce limits for medical assessments.