Sensation seeking has been described as a trait referring to the tendency to seek novel, varied, complex, and intense sensations and experiences; and the willingness to take risks for the sake of such experiences. Explanations for sensation seeking have been based upon genetic, evolutionary, psychophysiological, and sociocultural models. This study further examines the possibility that prenatal hormones - as measured via 2D:4D finger length ratio - may influence the development of certain personality characteristics associated with sensation seeking (Austin, Manning, McInroy, & Mathews, 2002). We studied the relationship between 2D:4D ratios, a supposed proxy for prenatal testosterone (T), and sensation seeking as assessed by the Sensation Seeking Scale Form V (SSS-V) in a sample of 278 German and UK University students. There were significant sex differences for 2D:4D and on the SSS-V, with males having lower 2D:4D ratios, but higher SSS-V scores. Furthermore, right- and left-hand 2D:4D in males was significantly negatively associated with total sensation seeking score, and the boredom subscale. No significant associations were found for women. Since low 2D:4D is supposed to indicate exposure to higher levels of T in utero, our data suggest that there may be an organizational effect of T which influences later development of sensation seeking personality characteristics in men.