The therapeutic relationship explains an important part of variability in clinical success. However, in academic literature there is yet to be a consensus on its definition. There are no instruments that assess the report of therapists and consultants from the behavioral approach. Likewise, in Colombia there is no recent research or validated instruments for this purpose. In this investigation, a factorial exploratory analysis was made on the Working Alliance Inventory –WAI– in therapists, a globally recognized instrument based on an inter-theoretical posture. From the results, an excellent reliability was found, with a Cronbach Alpha of 0.91. When applying the inventory on a local level, the extracted factorial structure does not correspond with the proposed dimensions on a theoretical level.