Marital satisfaction, involving 150 couples selected at-large and 40 couples in therapy, was investigated in two studies. An initial focus was the development of a 280-item Marital Satisfaction Inventory (MSI) including one validity scale, one global affective scale, and nine additional scales focusing on specific areas of marital interaction. Correlational analyses confirmed that measures of communication are the best single predictors of global marital satisfaction. Profile analyses demonstrated the ability of the MSI to discriminate between couples in therapy and a matched control group. General indications for clinical use of the instrument as an assessment and therapeutic tool suggest that it more clearly directs the focus of therapeutic intervention. (Author)