The outcome of psychotherapy in 30 patients with chronic ulcerative colitis was correlated with factors arising from the psychotherapeutic situation. Factors introduced by the therapist included his technical interventions, his personality, his attitudes toward the patient, his competence, and his grasp of the patient's psychodynamics. Patient factors included the latter's attitudes toward his illness and toward psychotherapy, his ability to change unfavorable life situations, the quality of his object relationships, his reactions to object loss, and his capacity for ego strengthening. Other factors were the frequency of sessions and the duration of psychotherapy. Interpretation, support, emotional abreaction, and direct suggestion were variably effective with different types of patients. Individuated patients did well with interpretation and abreaction. Symbiotic patients did better with support, suggestion, and graded abreaction. The fit between the patient's dependency needs and style of expressing them and the therapist's responsiveness to them was particularly important to the outcome. Therapist's interest, empathy, and optimism when combined with his patient's hopefulness produced the highest improvement rate. The patient's ability to change unfavorable life situations helped to maintain improvement. Psychoanalysis was indicated in selected patients. Less intensive psychotherapy helped the majority. Longer therapies generally gave more lasting results.