Working Alliance Inventory (WAI) ratings were compared with ratings comprising the 12-item WAI, Short Form (WAI-S). Responses were collected from 54 university counseling center client-therapist pairs after the 4th therapy session as well as at a final ratings point. WAI and WAI-S scores were highly correlated and had comparable descriptive statistics, internal consistencies, and subscale intercorrelations within and across rater perspectives. Predictive validity estimates for WAI and WAI-S total scales were also very similar. Fourth-session WAI and WAI-S scores were moderately predictive of therapy improvement ratings. Results support the interchangeability of scores on the WAI and WAI-S scales.