Knowledge about methods and materials and their correct usage is the basis for compression therapy. This study compares knowledge and practical skills of participants with further training with those who had no training. This comparison provides information on whether further qualifications have an impact on knowledge and practical skills. In seminars for compression therapy, data on specific and non-specific expertise were acquired. A practical test determined the participants' skills for creating a compression bandage in a pressure value range of 50-60 mmHg. In total, 1338 participants with specific expertise and 138 participants with non-specific expertise took part. Knowledge evaluation showed that 7·9% of the specific expertise group had knowledge regarding padding, 10% regarding multi-component systems and 13·6% regarding ulcer stocking systems. In the practical test, 12·3% of all participants achieved the target range. The majority of users in both groups is not familiar with the different compression materials or their appropriate usage. In the non-specific expertise group, knowledge concerning up-to-date materials and methods is one-third lower. The practical test showed major deficits on both sides. Appropriate exercises, for example, with pressure-measuring devices, should be mandatory for all professional groups who perform compression bandaging.