Recent years have seen increasing interest in devising methods of studying psychodynamic phenomena. These efforts have had confront difficulties, first, in specifying the data, the observation language, and rules of inference for psychodynamic propositions, and second, in determining the reliability and validity of the measures used. Given how "fuzzy" traditional psychodynamic concepts are, it is no wonder that psychodynamic clinicians from Freud onward have achieved more success in generating new hypotheses than in testing their validity. As Reichenbach (1938) has observed, science requires that discovery be followed by systematic validation of all new propositions, regardless of their degree of popular acceptance. At the core of efforts to study psychodynamics have been methods to study ego functioning (Bellak and Goldsmith 1984), defense mechanisms (Perry and Copper 1988), and psychodynamic conflicts. This paper reports on the reliability of the Idiographic Conflict Formulation (ICF), a guided method for formulating an individual's psychodynamic conflicts.