Background: This study aimed to develop and preliminarily validate a self-report inventory of the patterns of thoughts, feelings, and behaviors of the therapist toward the patient during an individual psychotherapy session using modern psychometric methods. Methods: An initial pool of 116 items was generated and its quality was evaluated by subject matter experts. Validation data was gathered from licensed psychotherapists (N=554). Exploratory factor analysis (EFA) and item response theory–graded response modeling were used to select items, confirmatory factor analysis (CFA) to determine whether the factor structure fitted the data well, and k-fold cross-validation to ascertain the robustness of the model. Criterion validity was evaluated by correlating the scale’s scores with the characteristics of therapists, patients, and treatment.Results: The Clinician Affective REsponse (CARE) scale has a three-factor structure: Positively Engaged (k=5, α=.77), Enmeshed (k=5, α=.73), and Stuck (k=5, α=.76). CFA provided the following fit indices: X2/df=1.53, CFI=.98, TLI=.97, RMSEA=.03, and SRMR=.04; whereas K-fold cross-validation (k=4) fit indices were: X2/df=1.44, CFI=.96, TLI=.96, RMSEA=.04, and SRMR=.05. The positively engaged subscale correlated positively with the Global Assessment of Functioning (GAF) score (r=.17, p<.001). The Enmeshed subscale correlated positively with therapy duration (r=.14, p<.001). The Stuck subscale correlated negatively with the GAF score (r=-.25, p<.001) and positively with the Clinical Global Impressions score (r=.19, p<.001).Discussion: Results provide preliminary evidence for the validity and reliability of the CARE scale and suggest that it may be a valuable tool in clinical, training, or research settings, useful for capturing the clinicians’ session-level emotional processes.