Internal working models of attachment are claimed to be unconscious structures operating outside the conscious awareness. Existing measures of attachment are almost exclusively explicit, either self-reports or interviews and it is questionable whether these instruments are able to tap into unconscious attachment attitudes. The main purpose of the present study is to develop Implicit Association Test (IAT) tools for assessing adult attachment and to examine their construct validity. Two sets of implicit attachment measures, based on the two-dimensional attachment model (Bartholomew & Horowitz, 1991), were developed. Convergent validity was assessed by examining (1) the relationship between implicit model of self and implicit self-esteem and (2) the relationship between the implicit model of other and implicit sociability. Divergent validity of attachment IATs was assessed by examining the relationship between the explicit and implicit attachment. The results showed support for convergent validity of the IAT Model of Self and for divergent validity.