Meta-analysis and reviews on sexual recidivism consistently report that sexual preference for children is one of the strongest predictors for reoffending in child molesters. The aim of our study is to introduce a new powerful implicit stimulus for the detection of sexual preference in child molesters with and without the clinical diagnosis of paedophilia. During the early 1970s Gunnar Johansson (1973) introduced Point- Light-Walkers (PLWs) as a new stimulus to perception research. He found that 12 lights fixed at the major joints of a moving person are sufficient to identify socially relevant features and the kind of actions displayed. Looking at the vast amount of literature on biological motion perception, we think that the ecological power combined with the ambiguity of PLWs make them appropriate as a new stimulus for forensic research dealing with sexual preference. The current study was performed in order to determine differences in attractiveness-ratings of PLWs between child molesters with (n = 44) and without (n = 21) the ICD-10 diagnosis of paedophilia and a control group of non-sex offenders (n = 68). We assume that sexual preference for underage girls and boys respectively is associated with higher attractiveness- ratings for female or male walking-patterns of children. We used logistic regression analysis to differentiate between different subgroups of child molesters and non-sex offenders. Attractivenessratings for female walking-patterns of children were the strongest predic77 tor for the diagnosis of paedophilia. Overall correct-classification rates varied from 74.6-76.1%, positive predictive values from 65.0-80.0% and negative predictive values from 68.8-77.6%. Our results on predictive power are at least comparable to the findings of phallometric measures (Abel et al., 1998) and implicit association methods (Gray et al., 2005). Nevertheless any single psychometric measure can never be sufficient enough to verify or rule out an individual clinical diagnosis of paedophilia.