Many clients drop out of therapy before reaching their goals; and research has yet to develop a thorough understanding of the factors that lead to dropout. Some have suggested that experiencing therapy as helpful or productive is key to therapy persis- tence. A small body of qualitative research has investigated client perspectives about things that happen during therapy sessions to produce change or therapy productiveness. The present study describes the process of developing and refining an instrument used to measure client perception of therapy productiveness in a sample of participants seeking therapy with a marriage and family therapist. Seventy-two participants engaged in therapy and completed the Productive Processes Inventory (PPI). Procedures used to establish reliability and validity are presented and discussed. Results of a principle components analysis revealed three factors. Results support the potential usefulness of the PPI as a measure of therapy productiveness.