This paper presents preliminary data on the psychometric and clinical properties of the Inventory of Interpersonal Problems (IIP: Horowitz, Rosenberg, Baer, Ureno & Villasenor, 1988) obtained from a UK sample of clients presenting with depression/anxiety for individual psychotherapy as part of two concurrent outcome studies: the Second Sheffield Psychotherapy Project (SPP2) and the Medical Research Council/NHS Collaborative Psychotherapy Project (CPP). The factor structure of the IIP is reported on a sample of 250 clients and eight factor-analytically derived scales are presented. Data on the reliability of the IIP together with its relationship to the Symptom Checklist-90R (SCL-90R: Derogatis, 1983) are investigated in a subsample of 143 clients. In addition, data are presented on the clinical relevance of the IIP using case material. The structure of the IIP was further analysed using ipsatized scores. Four bipolar factors were extracted and these findings are discussed with reference to four primary sets of social competencies.