The use of saliva samples is an alternative to blood samples when a large number of control samples are to be compared by DNA investigations. The most convenient and safe method is by using cotton wool swabs. In this investigation the average DNA content of saliva samples taken by three different sampling techniques (i. e. cotton wool swab, filter paper, liquid saliva) was compared. In addition the possibility of a DNA mixture of saliva samples after intensive kissing was investigated by taking samples from voluntary pairs. Mixed STR patterns were found in five samples but restricted to the first sampling after kissing within max. 60 s.