Fifty-two patients with spider phobia, fulfilling the DSM-III-R criteria for simple phobia, were assessed with behavioral, physiological and self-report measures. They were randomly assigned to five different treatment conditions: (1) one session therapist-directed exposure (maximum 3 hours), (2) specific manual-based treatment in the home, (3) specific manual-based treatment at the clinic, (4) general manual-based treatment in the home and (5) general manual-based treatment at the clinic. The results show that therapist-directed one-session treatment was significantly more effective than three of the manual-based treatments, both at the post-treatment and follow-up stages. Specific manual-based treatment at the clinic was significantly more successful than the other manual-based treatments, but only at follow-up. The proportion of clinically significant improved patients at follow-up was 80% in the therapist-directed group compared to 63% for the specific manual-based treatment at the clinic, 10% for specific manual-based treatment in the home, 9% for general manual-based treatment in the home, and 10% for general manual-based treatment at the clinic. The conclusion that can be drawn is that one-session therapist-directed treatment is the treatment of choice for spider phobia but manual-based treatment is a good alternative in some cases.