Of 120 pathological gamblers randomly allocated to imaginal desensitisation (ID) or to other behavioural procedures (60 to each group, all procedures administered over one week) 63 subjects were contacted two to nine years later. Twenty-six of the 33 who received ID reported control or cessation of gambling compared with 16 of 30 who received other behavioural procedures. This difference was significant, indicating ID had a specific effect additional to that of the other behavioural procedures. It is suggested the other procedures could be regarded as placebos. As the response at a mean of over five years to one week of ID is comparable with that reported to more intensive therapies, after briefer follow-up, it is suggested ID is a cost-effective therapy for pathological gambling, and is worth considering when resources are limited.