Embryoid bodies (EB) derived from pluripotent embryonic stem cells (ES) are powerful tools for different purposes. One interesting aspect is vessel development and the use for simulating angiostatic effects of drugs. Unfortunately, it is difficult to compare the impacts of different drugs. Current methods allow the description of observations, but quantifying methods are missing. To overcome that gap, we have developed a score system to transfer microscopic observations into quantifiable values. The score system summarizes different vessel characteristics within few categories and allows the comparison of drug effects in view of time and dosage. We analysed score behaviour with respect to normal vessel development as well as under presence of angiotstatic drugs. The vessel score showed a time-dependent increase under normal conditions while under presence of an angiogenesis-inhibitor the score increase was slowed, and under angiogenesis enhancing conditions the score increase was accelerated. The presented vessel development score seems to be a helpful tool to transfer microscopic observations in EB vessel development into a quantifiable and comparable value.